Powered by Deep Web Technologies
Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Materials' Deformation Dynamics at Atomic Scale In situ Atomic ...  

Science Conference Proceedings (OSTI)

Presentation Title, Materials' Deformation Dynamics at Atomic Scale In situ Atomic .... What Can We Learn from Measurements of Li-ion Battery Single Particles?

2

Atomic-scale investigations of the struct. and dynamics of complex catalytic materials  

DOE Green Energy (OSTI)

Prerequisite to the non-empirical design and refinement of improved catalysts is the identification of the atomic-scale structure and properties of the catalytically active sites. This has become a major industrial research priority. The focus of this research program was to combine atomic-resolution Z-contrast electron microscopy with first-principles density functional theory calculations to deliver an atomic-scale description of heterogeneous catalytic systems that could form the basis for non-empirical design of improved catalysts with greater energy efficiency.

Karl Sohlberg, Drexel University

2007-05-16T23:59:59.000Z

3

Atomic-scale investigations of the struct. and dynamics of complex catalytic materials  

SciTech Connect

By some accounts, catalysis impacts ? 30% of GDP in developed countries [Maxwell, I. E. Nature 394, 325-326 (1998)]. Catalysis is the enabling technology for petroleum production, for control of gaseous emissions from petroleum combustion, and for the production of industrial and consumer chemicals. Future applications of catalysis are potentially even more far reaching. There is an ever-growing need to move the economy from a fossil-fuel energy base to cleaner alternatives. Hydrogen-based combustion systems and fuel cells could play a dominant role, given a plentiful and inexpensive source of hydrogen. Photocatalysis is the most promising clean technology for hydrogen production, relying solely on water and sunlight, but performance enhancements in photocatalysis are needed to make this technology economically competitive. Given the enormously wide spread utilization of catalysts, even incremental performance enhancements would have far-reaching benefits for multiple end-use sectors. In the area of fuel and chemical production, such improvements would translate into vast reductions in energy consumption. At the consumption end, improvements in the catalysts involved would yield tremendous reductions in pollution. In the area of photocatalysis, such efficiency improvements could finally render hydrogen an economically viable fuel. Prerequisite to the non-empirical design and refinement of improved catalysts is the identification of the atomic-scale structure and properties of the catalytically active sites. This has become a major industrial research priority. The focus of this research program was to combine atomic-resolution Z-contrast electron microscopy with first-principles density functional theory calculations to deliver an atomic-scale description of heterogeneous catalytic systems that could form the basis for non-empirical design of improved catalysts with greater energy efficiency.

Karl Sohlberg, Drexel University

2007-05-16T23:59:59.000Z

4

Development of laser-plasma diagnostics using ultrafast atomic-scale dynamics. 96-ERD-046 final report  

Science Conference Proceedings (OSTI)

Ultrashort laser pulse systems allow examination of intense, ultrafast laser-plasma interactions. More specifically, intense laser irradiation can induce short xuv/x-ray bursts from the surface of condensed phase targets. Ultrafast xuv/x-ray detection is needed to understand laser-plasma interactions in this dynamic regime. Support of the Stockpile Stewardship and Management Program requires this critical understanding. Our effort here has been to extend understanding of atomic-scale dynamics in such environments with the goal of developing next generation ultrafast xuv/x-ray diagnostics where the sensors will be the atoms and ions themselves and the time resolution will approach that of the induced atomic transitions ({approx} a few femtoseconds). Pivotal contributions to the rapidly developing field of highly nonperturbative interactions of ultrashort pulse lasers with atoms/ions have been made at this laboratory. In the visible/infrared wavelength regions the temporal and spectral content of ultrashort laser pulses are now reliably monitored within a single pulse using frequency resolved optical gating (FROG) which is based on rapid nonlinear optical processes such as the Kerr effect. New applications of this basic concept are still being developed. Corresponding detection for the xuv/x-ray wavelengths does not exist and is urgently needed in many laboratory programs. The FROG technique cannot be applied in the xuv/x-ray region. Current x-ray streak camera technology is limited to {approx}0.5 picosecond resolution.

Bolton, P.R.; Kulander, K.C. [Lawrence Livermore National Lab., CA (United States); Boreham, B.W. [Central Queensland Univ., Rockhampton, QLD (Australia). Dept. of Applied Physics

1997-03-01T23:59:59.000Z

5

Atomic Scale Deformation Mechanisms of Amorphous Polyethylene ...  

Science Conference Proceedings (OSTI)

Atomic Scale Deformation Mechanisms of Amorphous Polyethylene under Tensile Loading · Atomistic Predictions of Age Hardening in Al-Cu Alloys.

6

Prospects for Atomic-Scale Tomography  

Science Conference Proceedings (OSTI)

Abstract Scope, Atomic-scale tomography (AST) may be defined as any technique that ... Initial Age Hardening and Nanostructural Evolution in a Cu-Ni-P Alloy.

7

Simulations of Kinetic Events at the Atomic Scale  

NLE Websites -- All DOE Office Websites (Extended Search)

of kinetic events at the atomic scale of kinetic events at the atomic scale Graeme Henkelman UT Austin Al / Al(100) B 3 I / Si Pd / MgO How can we simulate the dynamics of molecular systems over experimental time scales? Objective: To calculate dynamics of a surface over time scales which are much longer than can be calculated with direct classical dynamics. Problem: time scale gap fs ps ns ms ms s mins atomic dynamics thermally activated experimental vibrations simulations reaction dynamics time scales Most interesting transitions are rare 0.5 eV 1000/s events (much slower than vibrations) Simulating a transition for a typical rare event with classical dynamics can require ~10 12 force evaluations Transition state theory A statistical theory for calculating the rate of slow thermal processes

8

Atomic-scale Chemical Quantification of Oxide Interfaces Using ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Multifunctional Oxides. Presentation Title, Atomic-scale Chemical ...

9

Computational study of flow dynamics from a dc arc plasma jet  

E-Print Network (OSTI)

Plasma jets produced by direct-current (DC) non-transferred arc plasma torches, at the core of technologies ranging from spray coating to pyrolysis, present intricate dynamics due to the coupled interaction of fluid flow, thermal, and electromagnetic phenomena. The flow dynamics from an arc discharge plasma jet are investigated using time-dependent three-dimensional simulations encompassing the dynamics of the arc inside the torch, the evolution of the jet through the discharge environment, and the subsequent impingement of the jet over a flat substrate. The plasma is described by a chemical equilibrium and thermodynamic nonequilibrium (two-temperature) model. The numerical formulation of the physical model is based on a monolithic and fully-coupled treatment of the fluid and electromagnetic equations using a Variational Multiscale Finite Element Method. Simulation results uncover distinct aspects of the flow dynamics, including the jet forcing due to the movement of the electric arc, the prevalence of deviat...

Trelles, Juan Pablo

2013-01-01T23:59:59.000Z

10

An improved algorithm for maintaining arc consistency in dynamic constraint satisfaction problems  

E-Print Network (OSTI)

Real world is dynamic in its nature, so techniques attempting to model the real world should take this dynamicity in consideration. A well known Constraint Satisfaction Problem (CSP) can be extended this way to a so called Dynamic Constraint Satisfaction Problem (DynCSP) that supports adding and removing constraints in runtime. As Arc Consistency is one of the major techniques in solving CSPs, its dynamic version is of a particular interest for DynCSPs. This paper presents an improved version of AC|DC-2 algorithm for maintaining maximal arc consistency after constraint retraction. This improvement leads to runtimes better than the so far fastest dynamic arc consistency algorithm DnAC-6 while keeping low memory consumption. Moreover, the proposed algorithm is open in the sense of using either non-optimal AC-3 algorithm keeping a minimal memory consumption or optimal AC-3.1 algorithm improving runtime for constraint addition but increasing a memory consumption.

Roman Barták; Pavel Surynek

2005-01-01T23:59:59.000Z

11

Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.  

Science Conference Proceedings (OSTI)

Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

2011-06-01T23:59:59.000Z

12

Nano- and Atomic-Scale Fracture - Programmaster.org  

Science Conference Proceedings (OSTI)

Mar 29, 2011 ... About this Symposium. Meeting, Materials Science & Technology 2011. Symposium, Nano- and Atomic-Scale Fracture. Sponsorship, MS&T ...

13

Atomic Scale Investigation of Classical and Non-Classical Gamma ...  

Science Conference Proceedings (OSTI)

Direct experimental atomic scale evidence for such a mechanism will be ... Thermo-Kinetic Computer Simulation of Precipitation and Age-Hardening Effect in ...

14

Atomic Scale Modeling of Point Defects in Materials: Coupling Ab ...  

Science Conference Proceedings (OSTI)

Presentation Title, Atomic Scale Modeling of Point Defects in Materials: Coupling Ab Initio and Elasticity ... Electrochemical Shock of Lithium Battery Materials.

15

Nuclear Reactor Materials at the Atomic Scale - Programmaster.org  

Science Conference Proceedings (OSTI)

Presentation Title, Nuclear Reactor Materials at the Atomic Scale ... Study of the Interaction of Solutes with Interfaces in Iron Using Density-Functional Theory.

16

Atomic Scale Characterization of Complex Oxide Interfaces  

SciTech Connect

Complex oxides exhibit the most disparate behaviors, from ferroelectricity to high Tc superconductivity, colossal magnetoresistance to insulating properties. For these reasons, oxide thin films are of interest for electronics and the emerging field of spintronics. But epitaxial complex oxide ultrathin films and heterostructures can be significantly affected or even dominated by the presence of interfaces and may exhibit intriguing new physical properties quite different from the bulk. A study of the relations between structure and chemistry at the atomic scale is needed to understand the macroscopic properties of such "interface-controlled" materials. For this purpose, the combination of aberration corrected Z-contrast scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) represents a very powerful tool. The availability of sub- ngstr m probes allows a level of unprecedented detail when analyzing not only the interface structure with sensitivity to single atoms, but also the interface chemistry. In this work state of the art STEM-EELS will be applied to the study of different oxide interfaces in heterostructures with titanates, manganites and cuprates based on the perovskite structure.

Varela del Arco, Maria [ORNL; Pennycook, Timothy J [ORNL; Tian, Wei [ORNL; Mandrus, David [ORNL; Pennycook, Stephen J [ORNL; Pena, V. [Universidad Complutense, Spain; Sefrioui, Z. [Universidad Complutense, Spain; Santamaria, J. [Universidad Complutense, Spain

2006-01-01T23:59:59.000Z

17

Argonne CNM Highlight: Atomic Scale Modeling and Simulation of Silicon  

NLE Websites -- All DOE Office Websites (Extended Search)

Atomic Scale Modeling and Simulation of Silicon Anisotropic Etching Atomic Scale Modeling and Simulation of Silicon Anisotropic Etching N. Moldovan A well-known process in microelectromechanical systems (MEMS) technology involves etching silicon in alkaline solutions, which produces accurate 3-D silicon structures, sometimes with atomic smoothness, by taking advantage of the strong dependence of the etching rate on crystal orientation. Significant experimental effort has been made to characterize this anisotropy (polar etching rate diagrams, temperature dependencies, roughness measurements, in situ STM records during etching, electrochemistry studies etc.). The experimental results were used in complex simulations that successfully predicted the evolution of the 3-D geometry, starting from the experimentally measured etching diagrams.

18

Atomic Scale Characterization of Compound Semiconductors using Atom Probe Tomography: Preprint  

DOE Green Energy (OSTI)

Internal interfaces are critical in determining the performance of III-V multijunction solar cells. Studying these interfaces with atomic resolution using a combination of transmission electron microscopy (TEM), atom probe tomography (APT), and density functional calculations enables a more fundamental understanding of carrier dynamics in photovoltaic (PV) device structures. To achieve full atomic scale spatial and chemical resolution, data acquisition parameters in laser pulsed APT must be carefully studied to eliminate surface diffusion. Atom probe data with minimized group V ion clustering and expected stoichiometry can be achieved by adjusting laser pulse power, pulse repetition rate, and specimen preparation parameters such that heat flow away from the evaporating surface is maximized. Applying these improved analysis conditions to III-V based PV gives an atomic scale understanding of compositional and dopant profiles across interfaces and tunnel junctions and the initial stages of alloy clustering and dopant accumulation. Details on APT experimental methods and future in-situ instrumentation developments are illustrated.

Gorman, B. P.; Guthrey, H.; Norman, A. G.; Al-Jassim, M.; Lawrence, D.; Prosa, T.

2011-07-01T23:59:59.000Z

19

Simulations of kinetic events at the atomic scale Graeme Henkelman  

E-Print Network (OSTI)

Simulations of kinetic events at the atomic scale Graeme Henkelman UT Austin Al / Al(100) B3I / Si Need to find saddle points on the energy surface Rate of escape through each saddle point region: E (KMC): 1. Find low energy saddle points using a min-mode method. 2. Choose one processes from

20

APS/123-QED Understanding the atomic-scale contrast in Kelvin Probe Force  

E-Print Network (OSTI)

APS/123-QED Understanding the atomic-scale contrast in Kelvin Probe Force Microscopy Laurent Nony 1 are crucial to understand the atomic-scale KPFM signal. The calculations of the force #12;eld were performed

Recanati, Catherine

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

1995-01-01T23:59:59.000Z

22

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

Shimer, D.W.; Lange, A.C.

1995-05-23T23:59:59.000Z

23

Dosimetric properties of an amorphous-silicon EPID used in continuous acquisition mode for application to dynamic and arc IMRT  

Science Conference Proceedings (OSTI)

Dosimetric properties of an amorphous-silicon electronic portal imaging device (EPID) operated in a real-time acquisition mode were investigated. This mode will be essential for time-resolved dose verification of dynamic (sliding window) intensity modulated radiation therapy (IMRT) and intensity modulated arc radiation therapy (arc-IMRT). The EPID was used in continuous acquisition mode (i.e., ''cine'' mode) where individual sequential image frames are acquired in real time. The properties studied include dose linearity, reproducibility of response, and image stability. Results of using the continuous acquisition mode with several example treatments including dynamic IMRT, arc treatment, and single-arc-IMRT are compared to results using the well-studied integrated acquisition mode (i.e., ''frame averaging'' or ''IMRT'' mode). Real-time EPID response was also compared to real-time ion-chamber data for selected points in the deliveries. The example treatment deliveries in both continuous and integrated acquisition modes were converted to arbitrary EPID dose units via a calibration field. The summation of all acquired continuous mode images was compared using percentage dose difference to the single image acquired in the integrated mode using in-field pixels only (defined as those pixels >10% of maximum, in-field signal). Using the continuous acquisition mode, the EPID response was not linear with dose. It was found that the continuous mode dose response corresponded approximately to dropping one image per acquisition session. Reproducibility of EPID response to low monitor units (MUs) was found to be poor but greatly improved with increasing MU. Open field profiles were found to be stable in the cross-plane direction but required several frames to become stable in the in-plane direction. However, both of these issues are clinically insignificant due to arc-IMRT deliveries requiring relatively large monitor units (>100 MU). Analysis of the five IMRT, arc, and arc-IMRT tests revealed that all examples compared to within 2% of maximum dose for more than 95% of in-field pixels. The continuous acquisition mode is suited to time-resolved dosimetry applications including arc-IMRT and dynamic IMRT, giving comparable dose results to the well-studied integrated acquisition mode, although caution should be used in low MU applications. Time-resolved EPID dose information also compared well to time-resolved ion-chamber measurements.

McCurdy, B. M. C.; Greer, P. B. [Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Department of Radiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, New South Wales 2298 (Australia) and School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales 2308 (Australia)

2009-07-15T23:59:59.000Z

24

Electromagnetic-Guided Dynamic Multileaf Collimator Tracking Enables Motion Management for Intensity-Modulated Arc Therapy  

SciTech Connect

Purpose: Intensity-modulated arc therapy (IMAT) is attractive because of high-dose conformality and efficient delivery. However, managing intrafraction motion is challenging for IMAT. The purpose of this research was to develop and investigate electromagnetically guided dynamic multileaf collimator (DMLC) tracking as an enabling technology to treat moving targets during IMAT. Methods and Materials: A real-time three-dimensional DMLC-based target tracking system was developed and integrated with a linear accelerator. The DMLC tracking software inputs a real-time electromagnetically measured target position and the IMAT plan, and dynamically creates new leaf positions directed at the moving target. Low- and high-modulation IMAT plans were created for lung and prostate cancer cases. The IMAT plans were delivered to a three-axis motion platform programmed with measured patient motion. Dosimetric measurements were acquired by placing an ion chamber array on the moving platform. Measurements were acquired with tracking, without tracking (current clinical practice), and with the phantom in a static position (reference). Analysis of dose distribution differences from the static reference used a {gamma}-test. Results: On average, 1.6% of dose points for the lung plans and 1.2% of points for the prostate plans failed the 3-mm/3% {gamma}-test with tracking; without tracking, 34% and 14% (respectively) of points failed the {gamma}-test. The delivery time was the same with and without tracking. Conclusions: Electromagnetic-guided DMLC target tracking with IMAT has been investigated for the first time. Dose distributions to moving targets with DMLC tracking were significantly superior to those without tracking. There was no loss of treatment efficiency with DMLC tracking.

Keall, Paul J., E-mail: paul.keall@stanford.ed [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Sawant, Amit; Cho, Byungchul; Ruan, Dan; Wu Junqing; Poulsen, Per [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Petersen, Jay; Newell, Laurence J. [Calypso Medical Technologies, Seattle, WA (United States); Cattell, Herbert [Varian Medical Systems, Palo Alto, CA (United States); Korreman, Stine [Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Department of Human Oncology, University of Wisconsin-Madison, Madison, WI (United States)

2011-01-01T23:59:59.000Z

25

From the Micro to the Atomic-scale - Programmaster.org  

Science Conference Proceedings (OSTI)

Atomic-scale 3D Crystallographic Information Obtained from Atom Probe ... What Can We Learn from Measurements of Li-ion Battery Single Particles?

26

Dynamics of vaporization and dissociation during transient surface heating, with application to vacuum arcs  

SciTech Connect

This report describes a model of vaporization and dissociation occurring as a result of intense heating over a localized area of a material surface. The balance of heat between the input power and losses due to vaporization, as well as radiation and conduction in the material, are considered. The model includes the effect of binary mass diffusion and changes of surface stoichiometry for multiple component materials. Effects of vapor recondensation are included. The model is then applied to the description of spot heating on a vacuum arc anode through the use of a simple power feedback model. Comparison of surface temperature measurements to model predictions are used to parametrically describe the arc behavior. Finally, extensive parametric analyses showing the effect of material property variations on the arc behavior are described.

Benson, D.A.

1981-02-01T23:59:59.000Z

27

Image-Based Dynamic Multileaf Collimator Tracking of Moving Targets During Intensity-Modulated Arc Therapy  

SciTech Connect

Purpose: Intensity-modulated arc therapy (IMAT) enables efficient and highly conformal dose delivery. However, intrafraction motion may compromise the delivered target dose distribution. Dynamic multileaf collimator (DMLC) tracking can potentially mitigate the impact of target motion on the dose. The purpose of this study was to use a single kV imager for DMLC tracking during IMAT and to investigate the ability of this tracking to maintain the dose distribution. Methods: A motion phantom carrying a two-dimensional (2D) ion chamber array and buildup material with an embedded gold marker reproduced eight representative tumor trajectories (four lung tumors, four prostate). For each trajectory, a low and high IMAT plan were delivered with and without DMLC tracking. The three-dimensional (3D) real-time target position signal for tracking was provided by fluoroscopic kV images acquired immediately before and during treatment. For each image, the 3D position of the embedded marker was estimated from the imaged 2D position by a probability-based method. The MLC leaves were continuously refitted to the estimated 3D position. For lung, prediction was used to compensate for the tracking latency. The delivered 2D dose distributions were measured with the ion chamber array and compared with a reference dose distribution delivered without target motion using a 3%/3 mm {gamma}-test. Results: For lung tumor motion, tracking reduced the mean {gamma}-failure rate from 38% to 0.7% for low-modulation IMAT plans and from 44% to 2.8% for high-modulation plans. For prostate, the {gamma}-failure rate reduction was from 19% to 0% (low modulation) and from 20% to 2.7% (high modulation). The dominant contributor to the residual {gamma}-failures during tracking was target localization errors for most lung cases and leaf fitting errors for most prostate cases. Conclusion: Image-based tracking for IMAT was demonstrated for the first time. The tracking greatly improved the dose distributions to moving targets.

Poulsen, Per Rugaard, E-mail: perpolse@rm.dk [Institute of Clinical Medicine, Aarhus University, Aarhus (Denmark); Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Fledelius, Walther [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Cho, Byungchul [Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Keall, Paul [Sydney Medical School, University of Sydney, Sydney (Australia)

2012-06-01T23:59:59.000Z

28

Dynamic analysis of electric arcs based on energetic and Clarke approach  

Science Conference Proceedings (OSTI)

In the present paper an innovative approach to the transient study of interrupted single- and three-phase networks is proposed. It is based on state-equations and it is independent on the mathematical model adopted to represent the electric arc. In the ... Keywords: circuit breakers, switching transients, transient analysis

Francesco Della Torre; Sonia Leva; Adriano Paolo Morando

2008-07-01T23:59:59.000Z

29

Arc Welding  

Science Conference Proceedings (OSTI)

...work surface Radiation from the arc Thermal conduction from the arc plasma to the workpiece The first two mechanisms constitute the major source of energy to the

30

Atomic-Scale Chemical Imaging via Combination of Scanning Tunneling and Electron Energy Loss Spectroscopies  

E-Print Network (OSTI)

Atomic-Scale Chemical Imaging via Combination of Scanning Tunneling and Electron Energy Loss visualization of chemical reaction pathways to provide mechanistic understanding for catalytically important systems at atomic level Develop atomically resolved chemical imaging platform via combination of low

31

Atomic-Scale Imaging and Spectroscopy for In Situ Liquid Scanning Transmission Electron Microscopy  

Science Conference Proceedings (OSTI)

Observation of growth, synthesis, dynamics and electrochemical reactions in the liquid state is an important yet largely unstudied aspect of nanotechnology. The only techniques that can potentially provide the insights necessary to advance our understanding of these mechanisms is simultaneous atomic-scale imaging and quantitative chemical analysis (through spectroscopy) under environmental conditions in the transmission electron microscope (TEM). In this study we describe the experimental and technical conditions necessary to obtain electron energy loss (EEL) spectra from a nanoparticle in colloidal suspension using aberration corrected scanning transmission electron microscopy (STEM) combined with the environmental liquid stage. At a fluid path length below 400 nm, atomic resolution images can be obtained and simultaneous compositional analysis can be achieved. We show that EEL spectroscopy can be used to quantify the total fluid path length around the nanoparticle, and demonstrate characteristic core-loss signals from the suspended nanoparticles can be resolved and analyzed to provide information on the local interfacial chemistry with the surrounding environment. The combined approach using aberration corrected STEM and EEL spectra with the in situ fluid stage demonstrates a plenary platform for detailed investigations of solution based catalysis and biological research.

Jungjohann, K. L.; Evans, James E.; Aguiar, Jeff; Arslan, Ilke; Browning, Nigel D.

2012-06-04T23:59:59.000Z

32

The dosimetric impact of inversely optimized arc radiotherapy plan modulation for real-time dynamic MLC tracking delivery  

SciTech Connect

Purpose: Real-time dynamic multileaf collimator (MLC) tracking for management of intrafraction tumor motion can be challenging for highly modulated beams, as the leaves need to travel far to adjust for target motion perpendicular to the leaf travel direction. The plan modulation can be reduced by using a leaf position constraint (LPC) that reduces the difference in the position of adjacent MLC leaves in the plan. The purpose of this study was to investigate the impact of the LPC on the quality of inversely optimized arc radiotherapy plans and the effect of the MLC motion pattern on the dosimetric accuracy of MLC tracking delivery. Specifically, the possibility of predicting the accuracy of MLC tracking delivery based on the plan modulation was investigated. Methods: Inversely optimized arc radiotherapy plans were created on CT-data of three lung cancer patients. For each case, five plans with a single 358 deg. arc were generated with LPC priorities of 0 (no LPC), 0.25, 0.5, 0.75, and 1 (highest possible LPC), respectively. All the plans had a prescribed dose of 2 Gy x 30, used 6 MV, a maximum dose rate of 600 MU/min and a collimator angle of 45 deg. or 315 deg. To quantify the plan modulation, an average adjacent leaf distance (ALD) was calculated by averaging the mean adjacent leaf distance for each control point. The linear relationship between the plan quality [i.e., the calculated dose distributions and the number of monitor units (MU)] and the LPC was investigated, and the linear regression coefficient as well as a two tailed confidence level of 95% was used in the evaluation. The effect of the plan modulation on the performance of MLC tracking was tested by delivering the plans to a cylindrical diode array phantom moving with sinusoidal motion in the superior-inferior direction with a peak-to-peak displacement of 2 cm and a cycle time of 6 s. The delivery was adjusted to the target motion using MLC tracking, guided in real-time by an infrared optical system. The dosimetric results were evaluated using gamma index evaluation with static target measurements as reference. Results: The plan quality parameters did not depend significantly on the LPC (p {>=} 0.066), whereas the ALD depended significantly on the LPC (p < 0.001). The gamma index failure rate depended significantly on the ALD, weighted to the percentage of the beam delivered in each control point of the plan (ALD{sub w}) when MLC tracking was used (p < 0.001), but not for delivery without MLC tracking (p {>=} 0.342). The gamma index failure rate with the criteria of 2% and 2 mm was decreased from > 33.9% without MLC tracking to <31.4% (LPC 0) and <2.2% (LPC 1) with MLC tracking. Conclusions: The results indicate that the dosimetric robustness of MLC tracking delivery of an inversely optimized arc radiotherapy plan can be improved by incorporating leaf position constraints in the objective function without otherwise affecting the plan quality. The dosimetric robustness may be estimated prior to delivery by evaluating the ALD{sub w} of the plan.

Falk, Marianne; Larsson, Tobias; Keall, Paul; Chul Cho, Byung; Aznar, Marianne; Korreman, Stine; Poulsen, Per; Munck af Rosenschoeld, Per [Radiation Medicine Research Center, Department of Radiation Oncology - 3994, Rigshospitalet, Blegdamsvej 9, DK - 2100 Copenhagen (Denmark) and Niels Bohr Institute, University of Copenhagen (Denmark); Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital (Denmark); Radiation Physics Laboratory, Sydney Medical School, University of Sydney (Australia); Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Denmark and Niels Bohr Institute, University of Copenhagen (Denmark); Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital (Denmark); Niels Bohr Institute, University of Copenhagen (Denmark) and Department of Science, Systems and Models, Roskilde University (Denmark); Department of Oncology, Aarhus University Hospital (Denmark); Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital (Denmark) and Niels Bohr Institute, University of Copenhagen (Denmark)

2012-03-15T23:59:59.000Z

33

The ArcSDE GIS Dynamic Population Model Tool for Savannah River Site Emergency Response  

Science Conference Proceedings (OSTI)

The Savannah River Site (SRS) is a 310-square-mile Department of Energy site located near Aiken, South Carolina. With a workforce of over 10,000 employees and subcontractors, SRS emergency personnel must be able to respond to an emergency event in a timely and effective manner, in order to ensure the safety and security of the Site. Geographic Information Systems (GIS) provides the technology needed to give managers and emergency personnel the information they need to make quick and effective decisions. In the event of a site evacuation, knowing the number of on-site personnel to evacuate from a given area is an essential piece of information for emergency staff. SRS has developed a GIS Dynamic Population Model Tool to quickly communicate real-time information that summarizes employee populations by facility area and building and then generates dynamic maps that illustrate output statistics.

MCLANE, TRACY; JONES, DWIGHT

2005-10-03T23:59:59.000Z

34

Creating a Precise Atomic-Scale Map of Quantum Dots | Advanced Photon  

NLE Websites -- All DOE Office Websites (Extended Search)

Getting to the Roots of Lethal Hairs Getting to the Roots of Lethal Hairs Stressing Out the Twins in Magnesium Size-Related Behavior of Anatase Nanocrystals under Extreme Pressure Boron-Based Compounds Trick a Biomedical Protein A Targeted Cancer Treatment using Nanomaterials Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Creating a Precise Atomic-Scale Map of Quantum Dots OCTOBER 9, 2009 Bookmark and Share An atomic-scale map of the interface between an atomic dot and its substrate. Each peak represents a single atom. The map, made with high-intensity x-rays at the APS, is a slice through a vertical cross-section of the dot. (Image courtesy of Roy Clarke, University of

35

Elements of arc welding  

SciTech Connect

This paper looks at the following arc welding techniques: (1) shielded metal-arc welding; (2) submerged-arc welding; (3) gas metal-arc welding; (4) flux-cored arc welding; (5) electrogas welding; (6) gas tungsten-arc welding; and (7) plasma-arc welding.

1993-07-01T23:59:59.000Z

36

Spin-flip induction of Fano resonance upon electron tunneling through atomic-scale spin structures  

Science Conference Proceedings (OSTI)

The inclusion of inelastic spin-dependent electron scatterings by the potential profiles of a single magnetic impurity and a spin dimer is shown to induce resonance features due to the Fano effect in the transport characteristics of such atomic-scale spin structures. The spin-flip processes leading to a configuration interaction of the system's states play a fundamental role for the realization of Fano resonance and antiresonance. It has been established that applying an external magnetic field and a gate electric field allows the conductive properties of spin structures to be changed radically through the Fano resonance mechanism.

Val'kov, V. V., E-mail: vvv@iph.krasn.ru; Aksenov, S. V., E-mail: asv86@iph.krasn.ru [Russian Academy of Sciences, Siberian Branch, Kirensky Institute of Physics (Russian Federation); Ulanov, E. A. [Siberian State Aerospace University (Russian Federation)

2013-05-15T23:59:59.000Z

37

Atomic-scale structural analyses of epitaxial Co/Re superlattices  

Science Conference Proceedings (OSTI)

High-resolution transmission electron microscopy and scanning transmission electron microscopy (STEM) have been used to investigate atomic-scale structural properties of Co/Re trilayers and superlattices grown via magnetron sputtering. The sample growth was epitaxial with the (1010) plane of Co and Re parallel to the (1120) plane of Al{sub 2}O{sub 3}, and the [001] direction of Re and Co coinciding with that of the Al{sub 2}O{sub 3}. Both low-angle and high-angle Z-contrast STEM images show a very uniform layer thickness. However, the interface roughness between the Re and Co layers monotonically increases with interface distance from the substrate. These results strongly imply that, in the epitaxial Re/Co superlattice system, interface roughness plays a more important role in the giant magnetoresistance effect than thickness fluctuations of the spacer layer. Previous anisotropic magnetoresistance measurements can be explained in terms of the observed atomic-scale structure.

Xu Wentao; De Long, Lance E.; Charlton, Timothy; Chisholm, Matthew; Lederman, David [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Oak Ridge National Laboratory, P. O. Box 2008, MS6030-Oak Ridge, Tennessee 37831 (United States); Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2004-11-01T23:59:59.000Z

38

Method for large-scale fabrication of atomic-scale structures on material surfaces using surface vacancies  

DOE Patents (OSTI)

A method for forming atomic-scale structures on a surface of a substrate on a large-scale includes creating a predetermined amount of surface vacancies on the surface of the substrate by removing an amount of atoms on the surface of the material corresponding to the predetermined amount of the surface vacancies. Once the surface vacancies have been created, atoms of a desired structure material are deposited on the surface of the substrate to enable the surface vacancies and the atoms of the structure material to interact. The interaction causes the atoms of the structure material to form the atomic-scale structures.

Lim, Chong Wee (Urbana, IL); Ohmori, Kenji (Urbana, IL); Petrov, Ivan Georgiev (Champaign, IL); Greene, Joseph E. (Champaign, IL)

2004-07-13T23:59:59.000Z

39

Distribution Arc Flash  

Science Conference Proceedings (OSTI)

Arc flash from faults on 480-V circuits is a safety issue that can impact utility work. This report covers results from tests of arc flash and fabric performance from faults in 480-V network protectors and padmounted transformers. It supplements EPRI report 1018694, Distribution Arc Flash: Industry Practices and EPRI report 1018693, Distribution Arc Flash: Analysis Methods and Arc Characteristics.

2009-08-31T23:59:59.000Z

40

Atomic scale enhancement of the adhesion of beryllium films to carbon substrates  

Science Conference Proceedings (OSTI)

We have used 200 keV carbon ions to enhance the adhesion of 240-nm thick Be films to polished, vitreous carbon substrates. Adhesion of the as-deposited films was below that necessary to pass the scotch-tape test. Carbon ion fluences less than 1.6x10{sup 14} C/cm{sup 2} were sufficient to ensure the passage of the tape test without affecting the optical properties of the films. Adhesion failure of the as-deposited film was attributed to an inner oxide layer between the Be and the carbon. Because this oxide ({approximately}5 nm of BeO) was not measurably changed by the irradiation process, these results are consistent with adhesion enhancement occurring on the atomic scale at the interface between the inner oxide and the carbon substrate. This conclusion was supported by Rutherford backscattering (RBS) data, and potential adhesion mechanisms are discussed with consideration of relative contributions from electronic and nuclear stopping.

Musket, R.G.; Wirtenson, G.R.

1995-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Weld arc simulator  

DOE Patents (OSTI)

An arc voltage simulator for an arc welder permits the welder response to a variation in arc voltage to be standardized. The simulator uses a linear potentiometer connected to the electrode to provide a simulated arc voltage at the electrode that changes as a function of electrode position.

Burr, M.J.

1989-03-01T23:59:59.000Z

42

Dc arc weld starter  

DOE Patents (OSTI)

A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

Campiotti, R.H.; Hopwood, J.E.

1989-02-17T23:59:59.000Z

43

DC arc weld starter  

SciTech Connect

A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

Campiotti, Richard H. (Tracy, CA); Hopwood, James E. (Oakley, CA)

1990-01-01T23:59:59.000Z

44

Rates of tectonic and magmatic processes in the North Cascades continental magmatic arc  

E-Print Network (OSTI)

Continental magmatic arcs are among the most dynamic. geologic systems, and documentation of the magmatic, thermal, and tectonic evolution of arcs is essential for understanding the processes of magma generation, ascent ...

Matzel, Jennifer E. Piontek, 1973-

2004-01-01T23:59:59.000Z

45

Distribution Arc Flash  

Science Conference Proceedings (OSTI)

Arc flash from faults on distribution circuits is a safety issue that can impact work practices, protection requirements for line and substation workers, and relay and other overcurrent protection settings and practices. This report describes analysis methods and test results for EPRI-sponsored research on arc flash conducted in 2008.

2009-03-18T23:59:59.000Z

46

Adaptive-boost molecular dynamics simulation of carbon diffusion in iron  

E-Print Network (OSTI)

We have developed an accelerated molecular dynamics (MD) method to model atomic-scale rare events. In this method, a smooth histogram of collective variables is first estimated by canonical ensemble molecular dynamics ...

Ishii, Akio

47

Cathodic Arc Plasma Deposition  

Office of Scientific and Technical Information (OSTI)

Cathodic Arc Plasma Deposition Cathodic Arc Plasma Deposition André Anders Lawrence Berkeley National Laboratory, University of California, 1 Cyclotron Road, Mailstop 53, Berkeley, California 94720 aanders@lbl.gov Abstract Cathodic arc plasma deposition is one of oldest coatings technologies. Over the last two decades it has become the technology of choice for hard, wear resistant coatings on cutting and forming tools, corrosion resistant and decorative coatings on door knobs, shower heads, jewelry, and many other substrates. The history, basic physics of cathodic arc operation, the infamous macroparticle problem and common filter solutions are reviewed. Cathodic arc plasmas stand out due to their high degree of ionization, with important consequences for film nucleation, growth, and efficient utilization of substrate bias. The

48

Atomic-scale study of the adsorption of calcium fluoride on Si(100) at low-coverage regime  

Science Conference Proceedings (OSTI)

We investigate, experimentally and theoretically, the initial stage of the formation of Ca/Si and Si/F structures that occurs during the adsorption of CaF{sub 2} molecules onto a bare Si(100) surface heated to 1000 K in a low-coverage regime (0.3 monolayer). A low-temperature (5 K) scanning tunneling microscope (STM) is used to observe the topographies and the electronic properties of the exposed silicon surfaces. Our atomic-scale study reveals that several chemical reactions arise during CaF{sub 2} deposition, such as dissociation of the CaF{sub 2} molecules and etching of the surface silicon dimers. The experimental and calculated STM topographies are compared using the density functional theory, and this comparison enables us to identify two types of reacted structures on the Si(100) surface. The first type of observed complex surface structure consists of large islands formed with a semiperiodic sequence of 3 x 2 unit cells. The second one is made of isolated Ca adatoms adsorbed at specific sites on the Si(100)-2 x 1 surface.

Chiaravalloti, Franco; Dujardin, Gerald; Riedel, Damien [Institut des Sciences Moleculaires d'Orsay, UMR 8214, Universite Paris Sud, 91405 Orsay Cedex (France); Pinto, Henry P. [Interdisciplinary Center for Nanotoxicity, Department of Chemistry, Jackson State University, Jackson, Mississippi 39217-0510 (United States); Foster, Adam S. [Department of Applied Physics, Aalto Scool of Science, P.O. Box 11100, FI-00076 Aalto (Finland); Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33010 Tampere (Finland)

2011-10-15T23:59:59.000Z

49

Electric arc saw apparatus  

DOE Patents (OSTI)

A portable, hand held electric arc saw has a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc to erode a workpiece. Electric current is supplied to the blade by biased brushes and a slip ring which are mounted in the frame. A pair of freely movable endless belts in the form of crawler treads stretched between two pulleys are used to facilitate movement of the electric arc saw. The pulleys are formed of dielectric material to electrically insulate the crawler treads from the frame.

Deichelbohrer, Paul R. (Richland, WA)

1986-01-01T23:59:59.000Z

50

Welding arc initiator  

DOE Patents (OSTI)

An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome. 3 figs.

Correy, T.B.

1989-05-09T23:59:59.000Z

51

Welding arc initiator  

SciTech Connect

An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome.

Correy, Thomas B. (Richland, WA)

1989-01-01T23:59:59.000Z

52

Filtered cathodic arc source  

DOE Patents (OSTI)

Disclosed is a continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45{degrees} to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

Falabella, S.; Sanders, D.M.

1992-12-31T23:59:59.000Z

53

Filtered cathodic arc source  

DOE Patents (OSTI)

A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge is described. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45[degree] to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles. 3 figures.

Falabella, S.; Sanders, D.M.

1994-01-18T23:59:59.000Z

54

Electric arc saw apparatus  

DOE Patents (OSTI)

A portable, hand-held electric arc saw apparatus comprising a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc between the blade and a workpiece of opposite polarity. Electrically conducting means are provided on said frame for transmitting current to said blade. A pair of freely movable endless belts in the form of crawler treads are employed to facilitate movement of the apparatus relative to the workpiece.

Deichelbohrer, P.R.

1983-08-08T23:59:59.000Z

55

Distribution Arc Flash  

Science Conference Proceedings (OSTI)

Arc flash from faults on distribution circuits is a safety issue that can impact work practices, protection requirements for line and substation workers, and relay and other overcurrent protection settings and practices. Highlights of the research results are the following: Arcs did not sustain in any of the tests at 120/208 V in network protectors or meters. Because of low incident energies, only single-layer flame-retardant clothing is needed. Testing on medium-voltage equipment showed wide variability...

2011-03-08T23:59:59.000Z

56

Theory of Parabolic Arcs in Interstellar Scintillation Spectra  

E-Print Network (OSTI)

Our theory relates the secondary spectrum, the 2D power spectrum of the radio dynamic spectrum, to the scattered pulsar image in a thin scattering screen geometry. Recently discovered parabolic arcs in secondary spectra are generic features for media that scatter radiation at angles much larger than the rms scattering angle. Each point in the secondary spectrum maps particular values of differential arrival-time delay and fringe rate (or differential Doppler frequency) between pairs of components in the scattered image. Arcs correspond to a parabolic relation between these quantities through their common dependence on the angle of arrival of scattered components. Arcs appear even without consideration of the dispersive nature of the plasma. Arcs are more prominent in media with negligible inner scale and with shallow wavenumber spectra, such as the Kolmogorov spectrum, and when the scattered image is elongated along the velocity direction. The arc phenomenon can be used, therefore, to constrain the inner scale and the anisotropy of scattering irregularities for directions to nearby pulsars. Arcs are truncated by finite source size and thus provide sub micro arc sec resolution for probing emission regions in pulsars and compact active galactic nuclei. Multiple arcs sometimes seen signify two or more discrete scattering screens along the propagation path, and small arclets oriented oppositely to the main arc persisting for long durations indicate the occurrence of long-term multiple images from the scattering screen.

James M. Cordes; Barney J. Rickett; Daniel R. Stinebring; William A. Coles

2004-07-03T23:59:59.000Z

57

Soft arc consistency revisited  

Science Conference Proceedings (OSTI)

The Valued Constraint Satisfaction Problem (VCSP) is a generic optimization problem defined by a network of local cost functions defined over discrete variables. It has applications in Artificial Intelligence, Operations Research, Bioinformatics and ... Keywords: Constraint optimization, Graphical model, Local consistency, Soft arc consistency, Soft constraints, Submodularity, Valued constraint satisfaction problem, Weighted constraint satisfaction problem

M. C. Cooper; S. de Givry; M. Sanchez; T. Schiex; M. Zytnicki; T. Werner

2010-05-01T23:59:59.000Z

58

Hall-effect arc protector  

DOE Patents (OSTI)

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

Rankin, R.A.; Kotter, D.K.

1997-05-13T23:59:59.000Z

59

Hall-effect arc protector  

DOE Patents (OSTI)

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored.

Rankin, Richard A. (Ammon, ID); Kotter, Dale K. (Shelley, ID)

1997-01-01T23:59:59.000Z

60

VIDEO: Vacuum Arc Remelting - TMS  

Science Conference Proceedings (OSTI)

Apr 27, 2007 ... Video excerpts from Superalloys: Melting and Conversion showing the vacuum arc remelting process. SOURCE: TMS. Last Update: February ...

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

APPARATUS FOR ARC WELDING  

DOE Patents (OSTI)

An apparatus is described in which a welding arc created between an annular electrode and a workpiece moves under the influence of an electromagnetic field about the electrode in a closed or annular path. This mode of welding is specially suited to the enclosing of nuclear-fuel slugs in a protective casing. For example, a uranium slug is placed in an aluminum can, and an aluminum closure is welded to the open end of the can along a closed or annular path conforming to the periphery of the end closure.

Lingafelter, J.W.

1960-04-01T23:59:59.000Z

62

Electric arc welding gun  

DOE Patents (OSTI)

This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

Luttrell, Edward (Clinton, TN); Turner, Paul W. (Idaho Falls, ID)

1978-01-01T23:59:59.000Z

63

Arc fault detection system  

DOE Patents (OSTI)

An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

Jha, Kamal N. (Bethel Park, PA)

1999-01-01T23:59:59.000Z

64

Arc fault detection system  

DOE Patents (OSTI)

An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

Jha, K.N.

1999-05-18T23:59:59.000Z

65

Percussive arc welding apparatus  

DOE Patents (OSTI)

A percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.

Hollar, Jr., Donald L. (Overland Park, KS)

2002-01-01T23:59:59.000Z

66

Atomic-scale characterization of hydrogenated amorphous-silicon films and devices. Annual subcontract report, 14 February 1994--14 April 1995  

DOE Green Energy (OSTI)

Properties of the hydrogenated amorphous silicon (a-Si:H) films used in photovoltaic (PV) panels are reported. The atomic-scale topology of the surface of intrinsic a-Si:H films, measured by scanning tunneling microscopy (STM) as a function of film thickness, are reported and diagnosed. For 1-500-nm-thick films deposited under normal device-quality conditions from silane discharges, most portions of these surfaces are uniformly hilly without indications of void regions. However, the STM images indicate that 2-6-nm silicon particulates are continuously deposited into the growing film from the discharge and fill approximately 0.01% of the film volume. Although the STM data are not sensitive to the local electronic properties near these particulates, it is very likely that the void regions grow around them and have a deleterious effect on a-Si:H photovoltaics. Preliminary observations of particulates in the discharge, based on light scattering, confirm that particulates are present in the discharge and that many collect and agglomerate immediately downstream of the electrodes. Progress toward STM measurements of the electronic properties of cross-sectioned a-Si:H PV cells is also reported.

Gallagher, A.; Tanenbaum, D.; Laracuente, A.; Jelenkovic, B. [National Inst. of Standards and Technology, Boulder, CO (United States)

1995-08-01T23:59:59.000Z

67

Physics of arcing, and implications to sputter deposition  

E-Print Network (OSTI)

Series II. Mathematics, Physics and Chemistry vol. 88, I.Physics of arcing, and implications to sputter depositionleading to arcs and the physics of the arcing events

Anders, Andre

2005-01-01T23:59:59.000Z

68

Atomic Scale Quantum Nanoelectronics Laboratory  

Science Conference Proceedings (OSTI)

... quantized, leading to a range of new physical phenomena. ... and exploit such systems for future electronics, quantum information technologies, and ...

2012-07-20T23:59:59.000Z

69

Filters for cathodic arc plasmas  

DOE Patents (OSTI)

Cathodic arc plasmas are contaminated with macroparticles. A variety of magnetic plasma filters has been used with various success in removing the macroparticles from the plasma. An open-architecture, bent solenoid filter, with additional field coils at the filter entrance and exit, improves macroparticle filtering. In particular, a double-bent filter that is twisted out of plane forms a very compact and efficient filter. The coil turns further have a flat cross-section to promote macroparticle reflection out of the filter volume. An output conditioning system formed of an expander coil, a straightener coil, and a homogenizer, may be used with the magnetic filter for expanding the filtered plasma beam to cover a larger area of the target. A cathodic arc plasma deposition system using this filter can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

Anders, Andre (Albany, CA); MacGill, Robert A. (Richmond, CA); Bilek, Marcela M. M. (Engadine, AU); Brown, Ian G. (Berkeley, CA)

2002-01-01T23:59:59.000Z

70

Interpretation of parabolic arcs in pulsar secondary spectra  

E-Print Network (OSTI)

Pulsar dynamic spectra sometimes show organised interference patterns; these patterns have been shown to have power spectra which often take the form of parabolic arcs, or sequences of inverted parabolic arclets whose apexes themselves follow a parabolic locus. Here we consider the interpretation of these arc and arclet features. We give a statistical formulation for the appearance of the power spectra, based on the stationary phase approximation to the Fresnel-Kirchoff integral. We present a simple analytic result for the power-spectrum expected in the case of highly elongated images, and a single-integral analytic formulation appropriate to the case of axisymmetric images. Our results are illustrated in both the ensemble-average and snapshot regimes. Highly anisotropic scattering appears to be an important ingredient in the formation of the observed arclets.

Mark Walker; Don Melrose; Dan Stinebring; Chengmin Zhang

2004-03-25T23:59:59.000Z

71

Plasma arc torch with coaxial wire feed  

SciTech Connect

A plasma arc welding apparatus having a coaxial wire feed. The apparatus includes a plasma arc welding torch, a wire guide disposed coaxially inside of the plasma arc welding torch, and a hollow non-consumable electrode. The coaxial wire guide feeds non-electrified filler wire through the tip of the hollow non-consumable electrode during plasma arc welding. Non-electrified filler wires as small as 0.010 inches can be used. This invention allows precision control of the positioning and feeding of the filler wire during plasma arc welding. Since the non-electrified filler wire is fed coaxially through the center of the plasma arc torch's electrode and nozzle, the wire is automatically aimed at the optimum point in the weld zone. Therefore, there is no need for additional equipment to position and feed the filler wire from the side before or during welding.

Hooper, Frederick M (Albuquerque, NM)

2002-01-01T23:59:59.000Z

72

Prototype arc saw design and cutting trials  

SciTech Connect

A program was initiated to develop the arc saw as a tool capable of removing the end fittings from spent nuclear fuel bundles. A special arc saw for this purpose was designed, installed at the Pacific Northwest Laboratory and satisfactorily operated to remove end fittings from simulated, nonradioactive fuel bundles. The design of the arc saw included consideration of the cutting environment, power supply size, control equipment, and work piece size. Several simulated fuel bundles were cut to demonstrate that the arc saw met design specifications. Although the arc saw development program was curtailed before significant performance data could be collected, tests indicate that the arc saw is a good means of cropping spent fuel bundles and is well suited to remote operation and maintenance.

Allison, G.S.

1980-09-01T23:59:59.000Z

73

Miniaturized cathodic arc plasma source  

DOE Patents (OSTI)

A cathodic arc plasma source has an anode formed of a plurality of spaced baffles which extend beyond the active cathode surface of the cathode. With the open baffle structure of the anode, most macroparticles pass through the gaps between the baffles and reflect off the baffles out of the plasma stream that enters a filter. Thus the anode not only has an electrical function but serves as a prefilter. The cathode has a small diameter, e.g. a rod of about 1/4 inch (6.25 mm) diameter. Thus the plasma source output is well localized, even with cathode spot movement which is limited in area, so that it effectively couples into a miniaturized filter. With a small area cathode, the material eroded from the cathode needs to be replaced to maintain plasma production. Therefore, the source includes a cathode advancement or feed mechanism coupled to cathode rod. The cathode also requires a cooling mechanism. The movable cathode rod is housed in a cooled metal shield or tube which serves as both a current conductor, thus reducing ohmic heat produced in the cathode, and as the heat sink for heat generated at or near the cathode. Cooling of the cathode housing tube is done by contact with coolant at a place remote from the active cathode surface. The source is operated in pulsed mode at relatively high currents, about 1 kA. The high arc current can also be used to operate the magnetic filter. A cathodic arc plasma deposition system using this source can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

Anders, Andre (Albany, CA); MacGill, Robert A. (Richmond, CA)

2003-04-15T23:59:59.000Z

74

Purification of tantalum by plasma arc melting  

DOE Green Energy (OSTI)

Purification of tantalum by plasma arc melting. The level of oxygen and carbon impurities in tantalum was reduced by plasma arc melting the tantalum using a flowing plasma gas generated from a gas mixture of helium and hydrogen. The flowing plasma gases of the present invention were found to be superior to other known flowing plasma gases used for this purpose.

Dunn, Paul S. (Santa Fe, NM); Korzekwa, Deniece R. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

75

Dynamic  

Office of Legacy Management (LM)

Dynamic Dynamic , and Static , Res.ponse of the Government Oil Shale Mine at ' , . , Rifle, Colorado, to the Rulison Event. , . ; . . DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. p ( y c - - a 2-1 0 -4- REPORT AT (29-2) 914 USBM 1 0 0 1 UNITED STATES DEPARTMENT O F THE I NTERIOR BUREAU OF MINES e s.09 P. L. R U S S E L L RESEARCH D l RECTOR Februory 2, lB7O DYNAMIC AND STATIC RESPONSE 'OF THE GOVERNMENT OIL SHALE MINE A T RIFLE, COLORADO, T O THE, RULISON EVENT ORDER FROM CFSTl A S ~ B ~ &J C / This page intentionally left blank CONTENTS Page . . . . . . . . . . . . . . . . . . . . . . . . . H i s t o r i c . a l Des c r i p t i o n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction 3

76

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

Hawke, R.S.

1985-08-05T23:59:59.000Z

77

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

Hawke, Ronald S. (Livermore, CA)

1987-01-01T23:59:59.000Z

78

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile. 2 figs.

Hawke, R.S.

1987-11-17T23:59:59.000Z

79

Surface plasma-arc cutting of stainless steel  

Science Conference Proceedings (OSTI)

This danger does not exist when plasma-arc cutting is used. Plasma-arc cutting also increases productivity and produces better quality gouged surfaces [2].

80

An arc fault detection system  

DOE Patents (OSTI)

An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn, opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

Jha, Kamal N.

1997-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Theoretical analysis of ARC constriction  

DOE Green Energy (OSTI)

The physics of the thermionic converter is governed by strong electrode-plasma interactions (emissions surface scattering, charge exchange) and weak interactions (diffusion, radiation) at the maximum interelectrode plasma radius. The physical processes are thus mostly convective in thin sheaths in front of the electrodes and mostly diffusive and radiative in the plasma bulk. The physical boundaries are open boundaries to particle transfer (electrons emitted or absorbed by the electrodes, all particles diffusing through some maximum plasma radius) and to convective, conductive and radiative heat transfer. In a first approximation the thermionic converter may be described by a one-dimensional classical transport theory. The two-dimensional effects may be significant as a result of the sheath sensitivity to radial plasma variations and of the strong sheath-plasma coupling. The current-voltage characteristic of the converter is thus the result of an integrated current density over the collector area for which the boundary conditions at each r determine the regime (ignited/unignited) of the local current density. A current redistribution strongly weighted at small radii (arc constriction) limits the converter performance and opens questions on constriction reduction possibilities. The questions addressed are the followng: (1) what are the main contributors to the loss of current at high voltage in the thermionic converter; and (2) is arc constriction observable theoretically and what are the conditions of its occurrence. The resulting theoretical problem is formulated and results are given. The converter electrical current is estimated directly from the electron and ion particle fluxes based on the spatial distribution of the electron/ion density n, temperatures T/sub e/, T/sub i/, electrical voltage V and on the knowledge of the transport coefficients. (WHK)

Stoenescu, M.L.; Brooks, A.W.; Smith, T.M.

1980-12-01T23:59:59.000Z

82

Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydration Hydration Water on Rutile Studied by Backscattering Neutron Spectroscopy and Molecular Dynamics Simulation E. Mamontov,* ,† D. J. Wesolowski, ‡ L. Vlcek, § P. T. Cummings, §,| J. Rosenqvist, ‡ W. Wang, ⊥ and D. R. Cole ‡ Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, Chemical Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, Department of Chemical Engineering, Vanderbilt UniVersity, NashVille, Tennessee 37235-1604, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6496, and EnVironmental Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6036 ReceiVed: December 20, 2007; ReVised Manuscript ReceiVed: June 4, 2008 The high energy resolution, coupled with the wide dynamic range, of the new backscattering

83

Arc Flash Issues in Transmission and Substation Environments: Modeling of Incident Thermal Energy of Long Arcs  

Science Conference Proceedings (OSTI)

Arc flashes are a serious hazard that may put people in life-threatening situations and cause great damage to existing assets. The National Electrical Safety Code (NESC) and the Occupational Safety and Health Administration (OSHA) introduced requirements for electric utilities to perform arc flash hazard assessment of their facilities operating at and above 1000 V. Most methods available at this time for analyzing the incident thermal energy of arc flash were developed for low and medium-voltage industri...

2011-12-20T23:59:59.000Z

84

AdaptiveARC | Open Energy Information  

Open Energy Info (EERE)

AdaptiveARC AdaptiveARC Jump to: navigation, search Name AdaptiveARC Address 7683 Sitio Manana Place Carlsbad, California Zip 92009 Sector Biomass Product Waste-to-clean-energy startup is developing an arc-plasma reactor Website http://www.adaptivearc.com/ Coordinates 33.07959°, -117.22539° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":33.07959,"lon":-117.22539,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

85

Detection of arcs in automotive electrical systems  

E-Print Network (OSTI)

At the present time, there is no established method for the detection of DC electric arcing. This is a concern for forthcoming advanced automotive electrical systems which consist of higher DC electric power bus voltages, ...

Mishrikey, Matthew David

2005-01-01T23:59:59.000Z

86

RADIATION HAZARDS ENCOUNTERED IN ARC MELTING THORIUM  

SciTech Connect

A project to provide information on the hazards associated wlth arc melting of Th is described. A general airsampling analysis was made to determine the separation, concentration, and distribution of Th daughter (decay) products throughout arc melting, machining, and forging processes found in a handling facility. The value of well coordinated health physics program is stressed in connection with potential health hazards and personnel protection. Building, equipment, and exhaust ventilation requirements for such a facility are discussed, along wlth special handling methods. (auth)

Lowery, R.R.

1960-11-01T23:59:59.000Z

87

Groundwater Data Modeling for Arc Hydro  

E-Print Network (OSTI)

During the years 1999–2002, a consortium for geographic information systems (GIS) in water resources, led by the Center for Research in Water Resources (CRWR) and the Environmental Systems Research Institute (ESRI), developed a data model, named Arc Hydro, for the presentation of surface water data in ArcGIS. This model was published in the summer of 2002 (Maidment, 2002) and has since been adopted as a common framework by data producing agencies, such as the USGS, and by creators of hydrologic models requiring GIS data such as the Hydrologic Engineering Center and the Danish Hydraulic Institute. The Design of Arc Hydro revealed that it is possible to define a “hydrologic information system ” which is a synthesis of geospatial and temporal data supporting hydrologic analysis and modeling (Maidment, 2002). This is an exciting new concept because rather than simply applying GIS in water resources, it provides a new way of thinking about how information technology can be used to support water resources planning, modeling and management. While the first Arc Hydro data model focused on describing surface water behavior, it has become apparent that a similar effort is needed to define an ArcGIS data model for groundwater, as part of Arc Hydro. This need is emphasized by the lack of a well understood and generally agreed

unknown authors

2003-01-01T23:59:59.000Z

88

Apparatus for gas-metal arc deposition  

DOE Patents (OSTI)

Apparatus for gas-metal arc deposition of metal, metal alloys, and metal matrix composites. The apparatus contains an arc chamber for confining a D.C. electrical arc discharge, the arc chamber containing an outlet orifice in fluid communication with a deposition chamber having a deposition opening in alignment with the orifice for depositing metal droplets on a coatable substrate. Metal wire is passed continuously into the arc chamber in alignment with the orifice. Electric arcing between the metal wire anode and the orifice cathode produces droplets of molten metal from the wire which pass through the orifice and into the deposition chamber for coating a substrate exposed at the deposition opening. When producing metal matrix composites, a suspenion of particulates in an inert gas enters the deposition chamber via a plurality of feed openings below and around the orifice so that reinforcing particulates join the metal droplets to produce a uniform mixture which then coats the exposed substrate with a uniform metal matrix composite.

Buhrmaster, Carol L. (Corning, NY); Clark, Denis E. (Idaho Falls, ID); Smartt, Herschel B. (Idaho Falls, ID)

1991-01-01T23:59:59.000Z

89

Method for gas-metal arc deposition  

DOE Patents (OSTI)

Method and apparatus for gas-metal arc deposition of metal, metal alloys, and metal matrix composites. The apparatus contains an arc chamber for confining a D.C. electrical arc discharge, the arc chamber containing an outlet orifice in fluid communication with a deposition chamber having a deposition opening in alignment wiht the orifice for depositing metal droplets on a coatable substrate. Metal wire is passed continuously into the arc chamber in alignment with the orifice. Electric arcing between the metal wire anode and the orifice cathode produces droplets of molten metal from the wire which pass through the orifice and into the deposition chamber for coating a substrate exposed at the deposition opening. When producing metal matrix composites, a suspension of particulates in an inert gas enters the deposition chamber via a plurality of feed openings below and around the orifice so that reinforcing particulates join the metal droplets to produce a uniform mixture which then coats the exposed substrate with a uniform metal matrix composite.

Buhrmaster, Carol L. (Corning, NY); Clark, Denis E. (Idaho Falls, ID); Smartt, Herschel B. (Idaho Falls, ID)

1990-01-01T23:59:59.000Z

90

Method for gas-metal arc deposition  

DOE Patents (OSTI)

Method and apparatus for gas-metal arc deposition of metal, metal alloys, and metal matrix composites are disclosed. The apparatus contains an arc chamber for confining a D.C. electrical arc discharge, the arc chamber containing an outlet orifice in fluid communication with a deposition chamber having a deposition opening in alignment with the orifice for depositing metal droplets on a coatable substrate. Metal wire is passed continuously into the arc chamber in alignment with the orifice. Electric arcing between the metal wire anode and the orifice cathode produces droplets of molten metal from the wire which pass through the orifice and into the deposition chamber for coating a substrate exposed at the deposition opening. When producing metal matrix composites, a suspension of particulates in an inert gas enters the deposition chamber via a plurality of feed openings below and around the orifice so that reinforcing particulates join the metal droplets to produce a uniform mixture which then coats the exposed substrate with a uniform metal matrix composite. 1 fig.

Buhrmaster, C.L.; Clark, D.E.; Smartt, H.B.

1990-11-13T23:59:59.000Z

91

Magnetic Method to Characterize the Current Densities in Breaker Arc  

Science Conference Proceedings (OSTI)

The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc's current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing.

Machkour, Nadia [National Institute of Standards and Technology (United States)

2005-04-15T23:59:59.000Z

92

Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc  

E-Print Network (OSTI)

of the subducted slab on Aleutian Island Arc magma sources:2006. Revised age of Aleutian Island arc formation impliesCrustal recycling and the Aleutian arc. Geochim Cosmochim.

Yogodzinski, Gene

2011-01-01T23:59:59.000Z

93

Ion source with improved primary arc collimation  

DOE Patents (OSTI)

An improved negative ion source is provided in which a self-biasing, molybdenum collimator is used to define the primary electron stream arc discharge from a filament operated at a negative potential. The collimator is located between the anode and the filament. It is electrically connected to the anode by means of an appropriate size resistor such that the collimator is biased at essentially the filament voltage during operation. Initially, the full arc voltage appears across the filament to collimator until the arc discharge strikes. Then the collimator biases itself to essentially filament potential due to current flow through the resistor thus defining the primary electron stream without intercepting any appreciable arc power. The collimator aperture is slightly smaller than the anode aperture to shield the anode from the arc power which, in the past, has caused overheating and erosion of the anode collimator during extended time pulsed-beam operation of the source. With the self-biasing collimator of this invention, the ion source may be operated from short pulse periods to steady-state without destroying the anode.

Dagenhart, W.K.

1983-12-16T23:59:59.000Z

94

APPARATUS AND METHOD FOR ARC WELDING  

DOE Patents (OSTI)

An apparatus and method are given for forming a welding arc which is rotated by a magnetic field very rapidly about an annular electrode so that a weld is produced simultaneously over all points of an annular or closed path. This invention inhibits outgassing from the jacket of a fuel slug which is being welded by adjusting the pressure throughout the welding cycle to establish a balance between the gas pressure within the jacket and that of the atmosphere surrounding the jacket. Furthermore, an improved control of the magnetic field producing rotation of the welding arc is disclosed whereby this rotation is prevented from splashing about the metal being welded as the welding arc makes it molten.

Noland, R.A.; Stone, C.C.

1960-05-10T23:59:59.000Z

95

arcControlTower: the System for Atlas Production and Analysis on ARC  

E-Print Network (OSTI)

PanDA, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the job resources known in advance. All the pilot communication with the PanDA server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with the arcControl...

Filipcic, A; The ATLAS collaboration

2011-01-01T23:59:59.000Z

96

Corrosion and arc erosion in MHD channels  

DOE Green Energy (OSTI)

The objective of this task is to study the corrosion and arc erosion of MHD materials in a cooperative effort with, and to support, the MHD topping cycle program. Materials tested in the Avco Research Laboratory/Textron facility, or materials which have significant MHD importance, will be analyzed to document their physical deterioration. Conclusions shall be drawn about their wear mechanisms and lifetime in the MHD environment with respect to the following issues; sulfur corrosion, electrochemical corrosion, and arc erosion. The impact of any materials or slag conditions on the level of power output and on the level of leakage current in the MHD channel will also be noted, where appropriate.

Rosa, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering); Pollina, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering Avco-Everett Research Lab., Everett, MA (United States))

1991-10-01T23:59:59.000Z

97

Ion source based on the cathodic arc  

DOE Patents (OSTI)

A cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated, is described. An array of electrically isolated rings positioned in the source serves the dual purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles. 3 figures.

Sanders, D.M.; Falabella, S.

1994-02-01T23:59:59.000Z

98

American Ref Fuel Corporation ARC | Open Energy Information  

Open Energy Info (EERE)

Ref Fuel Corporation ARC Jump to: navigation, search Name American Ref-Fuel Corporation (ARC) Place Montvale, NJ, New Jersey Zip 76450 Product Focused on waste-to-energy facilities...

99

DOE Solar Decathlon: News Blog » SCI-Arc/Caltech  

NLE Websites -- All DOE Office Websites (Extended Search)

SCI-ArcCaltech Below you will find Solar Decathlon news from the SCI-ArcCaltech archive, sorted by date. New Zealand Takes First in Engineering Contest Thursday, September 29,...

100

LITTLEWOOD TYPE PROBLEMS ON SUB ARCS Peter ... - CECM  

E-Print Network (OSTI)

LITTLEWOOD TYPE. PROBLEMS ON SUB ARCS. Peter Borwein. Simon Fraser University Centre for. Constructive and Experimental. Mathematics.

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Toughened Graphite Electrode for High Heat Electric Arc ...  

Energy Innovation Portal Technologies. ... To reduce the failure rate, ... Applications and Industries. Electric arc furnace steel manufacturing;

102

Synthesis of Elementary Net Systems with Context Arcs and Localities  

Science Conference Proceedings (OSTI)

We investigate the synthesis problem for ENCL-systems, defined as Elementary Net Systems extended with context (inhibitor and activator) arcs and explicit event localities. Since colocated events are meant to be executed synchronously, the behaviour ... Keywords: Petri nets, activator arcs, context arcs, elementary net systems, inhibitor arcs, localities, net synthesis, step sequence semantics, structure and behaviour of nets, theory of concurrency, theory of regions, transition systems

Maciej Koutny; Marta Pietkiewicz-Koutny

2008-08-01T23:59:59.000Z

103

Out-arc pancyclicity of vertices in tournaments  

Science Conference Proceedings (OSTI)

Yao, Guo and Zhang [T. Yao, Y. Guo, K. Zhang, Pancyclic out-arcs of a vertex in a tournament, Discrete Appl. Math. 99 (2000) 245-249.] proved that every strong tournament contains a vertex u such that every out-arc of u is pancyclic. In this paper, we ... Keywords: Cycles, Out-arcs, Pancyclicity, Tournaments

Qiaoping Guo; Shengjia Li; Yubao Guo; Hongwei Li

2010-05-01T23:59:59.000Z

104

Gas tungsten arc welder with electrode grinder  

DOE Patents (OSTI)

A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable axial grinder is provided in the enclosure for refurbishing the used electrode between welds.

Christiansen, David W. (Kennewick, WA); Brown, William F. (West Richland, WA)

1984-01-01T23:59:59.000Z

105

Calculation of pressure waves in substation buildings due to arcing faults  

SciTech Connect

Pressure stress from internal arcing includes static and dynamic phenomena. These phenomena can be distinguished with the help of the pulsation factor. The ray tracing technique presented allows the three-dimensional calculation of pressure stresses including transient effects. Two examples demonstrating the importance of pressure waves on the stress of rooms are presented. A calculation procedure is given which enables an improvement of the design of substation buildings.

Dasbach, A.; Pietsch, G.J. (Grundegebiete der Elektrotechnik und Gasentladungstechnik, Aachen Univ. of Technology, Aachen (DE))

1990-10-01T23:59:59.000Z

106

arcControlTower, the System for Atlas Production and Analysis on ARC  

E-Print Network (OSTI)

Abstract content Panda, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the resources known in advance. All the pilot communication with the panda server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with t...

Filipcic, A; The ATLAS collaboration

2010-01-01T23:59:59.000Z

107

Probing Graphene Electronic Devices with Atomic Scale ...  

Science Conference Proceedings (OSTI)

... News Articles: Real-World Graphene Devices May Have a Bumpy Ride. Two Graphene Layers May Be Better Than One. ...

2012-06-06T23:59:59.000Z

108

Atomic-scale modeling platform for nanoelectronics  

Science Conference Proceedings (OSTI)

... Classical resistance. Quantum. resistance. ~50 nm. 2011-06-23 NIST workshop. QuantumWise. Slide 4. Slide 4. Current = propagation of wave function ...

2011-07-18T23:59:59.000Z

109

Atomic-scale modeling platform for nanoelectronics  

Science Conference Proceedings (OSTI)

... Quantum resistance ~50 nm Page 5. 2011-06-23 NIST workshop QuantumWise Slide 4 Slide 4 Current = propagation of wave function ...

2011-07-18T23:59:59.000Z

110

Atomic scale electron vortices for nanoresearch  

Science Conference Proceedings (OSTI)

Electron vortex beams were only recently discovered and their potential as a probe for magnetism in materials was shown. Here we demonstrate a method to produce electron vortex beams with a diameter of less than 1.2 Angst . This unique way to prepare free electrons to a state resembling atomic orbitals is fascinating from a fundamental physics point of view and opens the road for magnetic mapping with atomic resolution in an electron microscope.

Verbeeck, J.; Van Tendeloo, G. [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Schattschneider, P.; Loeffler, S. [Institute for Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Wien (Austria); Lazar, S. [FEI Electron Optics, 5600 KA Eindhoven (Netherlands); Canadian Centre for Electron Microscopy and Department of Materials Science and Engineering, McMaster University, Main Street West, Hamilton Ontario, L8S4M1 (Canada); Stoeger-Pollach, M.; Steiger-Thirsfeld, A. [USTEM, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Wien (Austria)

2011-11-14T23:59:59.000Z

111

Hybrid Arc Cell Studies: Status Report  

SciTech Connect

I report on the status, at the end of FY12, of the studies of an arc cell for a hybrid synchrotron accelerating from 375 GeV/c to 750 GeV/c in momentum. Garren produced a complete lattice that gives a good outline of the structure of a hybrid synchrotron lattice. It is, however, lacking in some details: it does not maintain a constant time of flight, it lacks chromaticity correction, its cell structure is not ideal for removing aberrations from chromaticity correction, and it probably needs more space between magnets. I have begun studying cell structures for the arc cells to optimize the lattice performance and cost. I present some preliminary results for two magnets per half cell. I then discuss difficulties encountered, some preliminary attempts at resolving them, and the future plans for this work.

Berg J. S.

2012-09-28T23:59:59.000Z

112

Surface breakdown igniter for mercury arc devices  

DOE Patents (OSTI)

Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

Bayless, John R. (Malibu, CA)

1977-01-01T23:59:59.000Z

113

Volumetric modulated arc radiotherapy for esophageal cancer  

SciTech Connect

A treatment planning study was performed to evaluate the performance of volumetric arc modulation with RapidArc (RA) against 3D conformal radiation therapy (3D-CRT) and conventional intensity-modulated radiation therapy (IMRT) techniques for esophageal cancer. Computed tomgraphy scans of 10 patients were included in the study. 3D-CRT, 4-field IMRT, and single-arc and double-arc RA plans were generated with the aim to spare organs at risk (OAR) and healthy tissue while enforcing highly conformal target coverage. The planning objective was to deliver 54 Gy to the planning target volume (PTV) in 30 fractions. Plans were evaluated based on target conformity and dose-volume histograms of organs at risk (lung, spinal cord, and heart). The monitor unit (MU) and treatment delivery time were also evaluated to measure the treatment efficiency. The IMRT plan improves target conformity and spares OAR when compared with 3D-CRT. Target conformity improved with RA plans compared with IMRT. The mean lung dose was similar in all techniques. However, RA plans showed a reduction in the volume of the lung irradiated at V{sub 20Gy} and V{sub 30Gy} dose levels (range, 4.62-17.98%) compared with IMRT plans. The mean dose and D{sub 35%} of heart for the RA plans were better than the IMRT by 0.5-5.8%. Mean V{sub 10Gy} and integral dose to healthy tissue were almost similar in all techniques. But RA plans resulted in a reduced low-level dose bath (15-20 Gy) in the range of 14-16% compared with IMRT plans. The average MU needed to deliver the prescribed dose by RA technique was reduced by 20-25% compared with IMRT technique. The preliminary study on RA for esophageal cancers showed improvements in sparing OAR and healthy tissue with reduced beam-on time, whereas only double-arc RA offered improved target coverage compared with IMRT and 3D-CRT plans.

Vivekanandan, Nagarajan, E-mail: viveknaren@hotmail.com [Department of Medical Physics, Cancer Institute, Chennai (India); Sriram, Padmanaban; Syam Kumar, S.A.; Bhuvaneswari, Narayanan; Saranya, Kamalakannan [Department of Medical Physics, Cancer Institute, Chennai (India)

2012-04-01T23:59:59.000Z

114

Arc Flash Issues in Transmission and Substation Environments  

Science Conference Proceedings (OSTI)

Arc flashes are a serious hazard that may potentially put people in life-threatening situations and cause great damage to existing assets. National Electrical Safety Code and Occupational Safety and Health Administration safety rules have introduced requirements for electric utilities to perform arc-flash hazard analysis of all electric facilities operating at and above 1000 volts. Most methods available at this time for analyzing the arc-flash incident thermal energy were developed for low- and medium-v...

2011-06-20T23:59:59.000Z

115

Recovering Zinc and Lead from Electric Arc Furnace Dust  

Science Conference Proceedings (OSTI)

Aug 1, 2000 ... Non-member price: 25.00. TMS Student Member price: 10.00. Product In Stock. Description Increasing amounts of electric arc furnace dust ...

116

Effects of Arc Welding Process on Microstructure and Morphology of ...  

Science Conference Proceedings (OSTI)

Presentation Title, Effects of Arc Welding Process on Microstructure and Morphology of Flake Graphite in Grey Cast Iron. Author(s), Arash Elhami Khorasani, ...

117

Combinatorics of Arc Diagrams, Ferrers Fillings, Young ... - CECM  

E-Print Network (OSTI)

Jul 22, 2009 ... I Generalization of permutation matrices: fill each row & column of a Ferrers shape ... Standard Young Tableaux. Arc Diagrams,. Nesting and.

118

Corrosion Behavior of Twin Wire Arc Sprayed Inconel Coating  

Science Conference Proceedings (OSTI)

Presentation Title, Corrosion Behavior of Twin Wire Arc Sprayed Inconel Coating. Author(s), Sofiane Djeraf, Yamina Mebdoua, Hadj Lahmar, Rachid Lakhdari.

119

ArcSafe® with Pulsed Arrested Spark Discharge  

NLE Websites -- All DOE Office Websites (Extended Search)

stress, aging electrical wiring systems, arc-physics, electrostatic dis- charge, and TEMPEST. R. Kevin Howard is a principle technologist with the Electromagnetic Technologies...

120

Method for controlling gas metal arc welding  

DOE Patents (OSTI)

The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections. 3 figs., 1 tab.

Smartt, H.B.; Einerson, C.J.; Watkins, A.D.

1987-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Method for controlling gas metal arc welding  

DOE Patents (OSTI)

The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections.

Smartt, Herschel B. (Idaho Falls, ID); Einerson, Carolyn J. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

1989-01-01T23:59:59.000Z

122

Modeling of thermal plasma arc technology FY 1994 report  

Science Conference Proceedings (OSTI)

The thermal plasma arc process is under consideration to thermally treat hazardous and radioactive waste. A computer model for the thermal plasma arc technology was designed as a tool to aid in the development and use of the plasma arc-Joule beating process. The value of this computer model is to: (a) aid in understanding the plasma arc-Joule beating process as applied to buried waste or exhumed buried waste, (b) help design melter geometry and electrode configuration, (c) calculate the process capability of vitrifying waste (i.e., tons/hour), (d) develop efficient plasma and melter operating conditions to optimize the process and/or reduce safety hazards, (e) calculate chemical reactions during treatment of waste to track chemical composition of off-gas products, and composition of final vitrified waste form and (f) help compare the designs of different plasma-arc facilities. A steady-state model of a two-dimensional axisymmetric transferred plasma arc has been developed and validated. A parametric analysis was performed that studied the effects of arc length, plasma gas composition, and input power on the temperatures and velocity profiles of the slag and plasma gas. A two-dimensional transient thermo-fluid model of the US Bureau of Mines plasma arc melter has been developed. This model includes the growth of a slag pool. The thermo-fluid model is used to predict the temperature and pressure fields within a plasma arc furnace. An analysis was performed to determine the effects of a molten metal pool on the temperature, velocity, and voltage fields within the slag. A robust and accurate model for the chemical equilibrium calculations has been selected to determine chemical composition of final waste form and off-gas based on the temperatures and pressures within the plasma-arc furnace. A chemical database has been selected. The database is based on the materials to be processed in the plasma arc furnaces.

Hawkes, G.L.; Nguyen, H.D.; Paik, S.; McKellar, M.G.

1995-03-01T23:59:59.000Z

123

Documentation of the operation of an arc-heated hydrogen atom source  

DOE Green Energy (OSTI)

A detailed description of the operation is given including establishment of an argon arc, changeover to hydrogen, and parameters of the hydrogen arc. A table of arc parameters for an 18 hour period is included. (GHT)

Way, K.R.; Yang, S.C.; Stwalley, W.C.

1976-02-11T23:59:59.000Z

124

What makes an electric welding arc perform its required function  

SciTech Connect

The physics of direct current and alternating current welding arcs, the heat transfer of direct current welding arcs, the characteristics of dc welding and ac welding power supplies and recommendations for the procurement and maintenance of precision power supplies are discussed. (LCL)

Correy, T.B.

1982-09-01T23:59:59.000Z

125

Physical characteristics of gliding arc discharge plasma generated in a laval nozzle  

Science Conference Proceedings (OSTI)

The dynamic behavior of gliding arc discharge generated in a Laval nozzle has been investigated by electrical diagnostics and a high-speed camera. The results show that the voltage waveform keeps the initial shape as the gas flow rate is small, while it becomes less stable with increasing flow rate. During the first half of a cycle, the voltage rises and after that it decreases. In nitrogen and oxygen, the break down voltage for the arc is between 3.3 and 5.5 kV, while it is between 3.3-7.5 kV in air. The waveform of current I remains almost stable; and for nitrogen and oxygen, the maximum value of current I is between 0.28 and 0.46 A. With increasing flow rate, the power consumption in air first increases and then decreases; it remains in the range of 110-217 W, and gradually increases in nitrogen and oxygen. The power consumption in oxygen is lower than that in nitrogen; the input of the energy density decreases with increasing flow rate for all the three gases. The development of the arc is tracked and recorded by a high-speed camera. The cycle is stable at 10 ms for flow rates up to 1 m{sup 3} h{sup -1}. At a higher flow rate, the cycle becomes unstable.

Lu, S. Y.; Sun, X. M.; Li, X. D.; Yan, J. H. [State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027 (China); Du, C. M. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

2012-07-15T23:59:59.000Z

126

Darwin: The Third DOE ARM TWP ARCS Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Darwin: The Third DOE ARM TWP ARCS Site Darwin: The Third DOE ARM TWP ARCS Site W. E. Clements and L. Jones Los Alamos National Laboratory, Los Alamos, New Mexico T. Baldwin Special Services Unit Australian Bureau of Meteorology Melbourne, Australia K. Nitschke South Pacific Regional Environment Programme Apia, Samoa Introduction The U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Program began operations in its Tropical Western Pacific (TWP) locale in October 1996 when the first Atmospheric Radiation and Cloud Station (ARCS) began collecting data on Manus Island in Papua New Guinea (PNG). Two years later, in November 1998 a second ARCS began operations on the island of Nauru in the Central Pacific. Now a third ARCS has begun collecting data in Darwin, Australia. See Figure 1 for

127

An arc flash is the result of a rapid release of energy due to an arcing fault between  

E-Print Network (OSTI)

- Standard for Electrical Safety in the Workplace requires that a flash hazard analysis be conductedAn arc flash is the result of a rapid release of energy due to an arcing fault between conductors. The conductive material usually burns away from the intense heat. If conditions are right, the flow of energy can

128

Manual gas tungsten arc (dc) and semiautomatic gas metal arc welding of 6XXX aluminum. Welding procedure specification  

SciTech Connect

Procedure WPS-1009 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for manual gas tungsten arc (DC) and semiautomatic gas metal arc (DC) welding of aluminum alloys 6061 and 6063 (P-23), in thickness range 0.187 to 2 in.; filler metal is ER4043 (F-23); shielding gases are helium (GTAW) and argon (GMAW).

Wodtke, C.H.; Frizzell, D.R.; Plunkett, W.A.

1985-08-01T23:59:59.000Z

129

A model-based approach to intelligent control of gas metal arc welding  

SciTech Connect

This paper discusses work on a model-based intelligent process controller for gas metal arc welding. Four sensors input to a neural network, which communicates to a reference model-based adaptive controller that controls process parameters. Reference model derivation and validation are discussed. The state of an arch weld is determined by the composition of the weld and base metal and the weld's thermomechanical history. The composition of the deposited weld metal depends primarily on the amount of filler metal dilution; heat input to the weld, comprising pre-heat and process heat, is the controlling factor in the thermal cycle. Thus, control of the arc welding process should focus on rational specification and in-process control of the heat and mass input to the weld. A control model has been developed in which the governing equations are solved for the process parameters as functions of the desired heat input (in terms of heat input unit weld length) and mass input (in terms of transverse reinforcement area) to the weld. The model includes resistive and arc heating of the electrode wire, characteristics of the welding power supply, and a volumetric heat balance on the electrode material, as well as latent and superheat of the electrode material. Extension of the model to include dynamics of individual droplet transfer events, based on incorporating a nonlinear, lumped parameter droplet analysis, is discussed. A major emphasis has been placed on computational simplicity; model solutions are required at the rate of about 10 Hz during welding. Finally, a process control scheme has been developed for the gas metal arc welding process using the above nonlinear model with a proportional-integral controller with adaptive coefficients to control the weld heat input and reinforcement area independently. Performance of the resulting control method is discussed. 10 refs., 5 figs.

Smartt, H.B.; Johnson, J.A.; Einerson, C.J.; Watkins, A.D.; Carlson, N.M.

1990-01-01T23:59:59.000Z

130

Waste Heat Recovery – Submerged Arc Furnaces (SAF)  

E-Print Network (OSTI)

Submerged Arc Furnaces are used to produce high temperature alloys. These furnaces typically run at 3000°F using high voltage electricity along with metallurgical carbon to reduce metal oxides to pure elemental form. The process as currently designed consumes power and fuel that yields an energy efficiency of approximately 40% (Total Btu’s required to reduce to elemental form/ Btu Input). The vast majority of heat is lost to the atmosphere or cooling water system. The furnaces can be modified to recover this heat and convert it to power. The system will then reduce the amount of purchased power by approximately 25% without any additional use of fuel. The cost of this power is virtually unchanged over the life of the project because of the use of capital to displace fuel consumed from the purchased power source.

O'Brien, T.

2008-01-01T23:59:59.000Z

131

Welding and Repair Technology Center: Gas Metal Arc Welding Lessons  

Science Conference Proceedings (OSTI)

Modern gas metal arc welding (GMAW) systems no longer operate with a symmetric, fixed pulse. The new systems have closed-loop feedback and are waveform-controlled systems that vary the arc characteristics hundreds of times per second to stabilize the arc. The main advantage of these systems is the ease of operation when manual applications are required or out-of-position welding is applied. The systems allow flexibility in the stand-off distance (contact tip to work distance) while maintaining an ...

2013-09-30T23:59:59.000Z

132

Back arc extension and collision: An experimental approach of the tectonics of Asia  

E-Print Network (OSTI)

arc basins (Japan Sea, Okinawa Trough, South China Sea) and continental grabens (North China grabens

133

DOE Solar Decathlon: News Blog » SCI-Arc/Caltech  

NLE Websites -- All DOE Office Websites (Extended Search)

SCI-Arc/Caltech SCI-Arc/Caltech Below you will find Solar Decathlon news from the SCI-Arc/Caltech archive, sorted by date. CHIP House Takes Design to Different Heights (Literally) Friday, May 13, 2011 By April Saylor Editor's Note: This entry has been cross-posted from DOE's Energy Blog. In honor of the U.S. Department of Energy Solar Decathlon-which challenges 20 collegiate teams to design, build, and operate solar-powered houses that are cost-effective, energy-efficient, and attractive-we are profiling each of the 20 teams participating in the competition. The students from the Southern California Institute of Architecture and California Institute of Technology, otherwise known as the SCI-Arc/Caltech team, have teamed up to take an interesting approach to the design of their

134

Capabilities of the ARCS Instrument - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Capabilities of the ARCS Instrument Capabilities of the ARCS Instrument ARCS Overview The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of 3He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and

135

Exhaust-gas measurements from NASAs HYMETS arc jet.  

Science Conference Proceedings (OSTI)

Arc-jet wind tunnels produce conditions simulating high-altitude hypersonic flight such as occurs upon entry of space craft into planetary atmospheres. They have traditionally been used to study flight in Earth's atmosphere, which consists mostly of nitrogen and oxygen. NASA is presently using arc jets to study entry into Mars' atmosphere, which consists of carbon dioxide and nitrogen. In both cases, a wide variety of chemical reactions take place among the gas constituents and with test articles placed in the flow. In support of those studies, we made measurements using a residual gas analyzer (RGA) that sampled the exhaust stream of a NASA arc jet. The experiments were conducted at the HYMETS arc jet (Hypersonic Materials Environmental Test System) located at the NASA Langley Research Center, Hampton, VA. This report describes our RGA measurements, which are intended to be used for model validation in combination with similar measurements on other systems.

Miller, Paul Albert

2010-11-01T23:59:59.000Z

136

Ohmic contacts for solar cells by arc plasma spraying  

DOE Patents (OSTI)

The method of applying ohmic contacts to a semiconductor, such as a silicon body or wafer used in solar cells, by the use of arc plasma spraying, and solar cells resulting therefrom.

Narasimhan, Mandayam C. (Seekonk, MA); Roessler, Barton (Barrington, RI); Loferski, Joseph J. (Providence, RI)

1982-01-01T23:59:59.000Z

137

Arc Flash Phase II Work Practices Survey Report  

Science Conference Proceedings (OSTI)

The Arc Flash Phase II Work Practices Survey was conducted as part of an EPRI project aimed at helping utilities understand and prepare for changing National Electrical Safety Code (NESC) and Occupational Safety and Safety Administration (OSHA) arc flash regulations. These changes can have significant implications for utility work practices, protective schema, and personal protection. The results of this survey are summarized in this report. The Phase II Survey is the second of two surveys EPRI has condu...

2009-12-18T23:59:59.000Z

138

Laser assisted non-consumable arc welding process development  

SciTech Connect

The employment of Laser Beam Welding (LBW) for many traditional arc welding applications is often limited by the inability of LBW to compensate for variations in the weld joint gap. This limitation is associated with fluctuations in the energy transfer efficiency along the weld joint. Since coupling of the laser beam to the workpiece is dependent on the maintenance of a stable absorption keyhole, perturbations to the weld pool can lead to decreased energy transfer and resultant weld defects. Because energy transfer in arc welding does not similarly depend on weld pool geometry, it is expected that combining these two processes together will lead to an enhanced fusion welding process that exhibits the advantages of both arc welding and LBW. Laser assisted non-consumable arc welds have been made on thin section aluminum. The welds combine the advantages of arc welding and laser welding, with enhanced penetration and fusion zone size. The use of a pulsed Nd:YAG laser with the combined process appears to be advantageous since this laser is effective in removing the aluminum oxide and thereby allowing operation with the tungsten electrode negative. The arc appears to increase the size of the weld and also to mitigate hot cracking tendencies that are common with the pulsed Nd:YAG laser.

Fuerschach, P.W.; Hooper, F.M.

1997-09-01T23:59:59.000Z

139

Method and apparatus for gas-metal arc deposition  

DOE Patents (OSTI)

Method and apparatus for gas-metal arc deposition of metal, metal alloys, and metal matrix composites are presented. The apparatus contains an arc chamber for confining a DC electrical arc discharge, the arc chamber containing an outlet orifice in fluid communication with a deposition chamber having a deposition opening in alignment with the orifice for depositing metal droplets on a coatable substrate. Metal wire is passed continuously into the arc chamber in alignment with the orifice. Electric arcing between the metal wire anode and the orifice cathode produces droplets of molten metal from the wire which pass through the orifice and into the deposition chamber for coating a substrate exposed at the deposition opening. When producing metal matrix composites, a suspension of particulates in an inert gas enters the deposition chamber via a plurality of feed openings below and around the orifice so that reinforcing particulates join the metal droplets to produce a uniform mixture which then coats the exposed substrate with a uniform metal matrix composite. 1 fig., 2 tabs.

Buhrmaster, C.L.; Clark, D.E.; Smartt, H.B.

1989-10-18T23:59:59.000Z

140

A Miocene Island-Arc Volcanic Seamount- The Takashibiyama Formation,  

Open Energy Info (EERE)

Island-Arc Volcanic Seamount- The Takashibiyama Formation, Island-Arc Volcanic Seamount- The Takashibiyama Formation, Shimane Peninsula, Sw Japan Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Miocene Island-Arc Volcanic Seamount- The Takashibiyama Formation, Shimane Peninsula, Sw Japan Details Activities (0) Areas (0) Regions (0) Abstract: The Miocene volcanic complex of the Takashibiyama Formation consists largely of subalkali, subaqueous basalt to andesite lavas and andesite to dacite subaqueous volcaniclastic flow deposits. Most of subaqueous lavas are moderately to intensely brecciated with rugged rough surfaces and ramp structures similar to subaerial block lava. Volcaniclastic flow deposits commonly include basalt to andesite lava fragments and/or pyroclastic materials, and are similar in internal

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Advanced RenewableEnergy Company ARC Energy | Open Energy Information  

Open Energy Info (EERE)

Advanced RenewableEnergy Company ARC Energy Advanced RenewableEnergy Company ARC Energy Jump to: navigation, search Name Advanced RenewableEnergy Company (ARC Energy) Place Nashua, New Hampshire Product New Hampshire-based stealth mode LED substrate manufacture equipment provider which aims to lower the cost of LEDs. Coordinates 42.758365°, -71.464209° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.758365,"lon":-71.464209,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

142

ArcSafe® with Pulsed Arrested Spark Discharge  

NLE Websites -- All DOE Office Websites (Extended Search)

ArcSafe® ArcSafe® with Pulsed Arrested Spark Discharge  2007 R&D 100 Award Entry Form ArcSafe® with Pulsed Arrested Spark Discharge  Joint Submitters Submitting Organization Sandia National Laboratories PO Box 5800, MS 1181 Albuquerque, NM 87185-1181 USA Larry Schneider Phone: (505) 845-7135 Fax: (505) 845-7685 Email: lxschne@sandia.gov AFFIRMATION: I affirm that all information submitted as a part of, or supplemental to, this entry is a fair and accurate represen- tation of this product. (Signature)______________________________________ Astronics-Advanced Electronic Systems, Inc. 9845 Willows Rd NE City: Redmond State: WA Zip/Postal: 98052-2540 USA Contact Name: Michael Ballas, Program Manager Phone: (425) 895-4304 Fax: (425)702.4930 Email: michael.ballas@astronics.com

143

High-bandwidth continuous-flow arc furnace  

DOE Patents (OSTI)

A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

Hardt, D.E.; Lee, S.G.

1996-08-06T23:59:59.000Z

144

Muon Acceleration with RLA and Non-scaling FFAG Arcs  

Science Conference Proceedings (OSTI)

Recirculating Linear Accelerators (RLA) are the most likely means to achieve the rapid acceleration of shortlived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper, we present a novel return-arc optics design based on a Non Scaling Fixed Field Alternating Gradient (NS-FFAG) lattice that allows 5 and 9 GeV/c muons of both charges to be transported in the same string of magnets. The return arcs are made up of super cells with each super cell consisting of three triplets. By employing combined function magnets with dipole, quadrupole, sextupole and octupole magnetic field components, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both 5 and 9 GeV/c muon momenta. This solution would reduce the number of arcs by a factor of 2, simplifying the overall design.

Vasiliy Morozov,Alex Bogacz,Dejan Trbojevic

2010-05-01T23:59:59.000Z

145

An ion source based on the cathodic arc  

DOE Patents (OSTI)

This invention is comprised of a cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated. An array of electrically isolated rings positioned in the source serves the duel purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles.

Sanders, D.M.; Falabella, S.

1992-12-31T23:59:59.000Z

146

Multi-cathode metal vapor arc ion source  

DOE Patents (OSTI)

An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam. One embodiment of the appaatus utilizes a multi-cathode arrangement for interaction with the anode.

Brown, Ian G. (1088 Woodside Rd., Berkeley, CA 94708); MacGill, Robert A. (645 Kern St., Richmond, CA 94805)

1988-01-01T23:59:59.000Z

147

Radiation in molecular dynamic simulations  

DOE Green Energy (OSTI)

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The new technique passes a key test: it relaxes to a blackbody spectrum for a plasma in local thermodynamic equilibrium. This new tool also provides a method for assessing the accuracy of energy and momentum exchange models in hot dense plasmas. As an example, we simulate the evolution of non-equilibrium electron, ion, and radiation temperatures for a hydrogen plasma using the new molecular dynamics simulation capability.

Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M

2008-10-13T23:59:59.000Z

148

Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source  

Science Conference Proceedings (OSTI)

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of {sup 3}He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

Abernathy, D. L.; Stone, M. B.; Loguillo, M. J.; Lucas, M. S.; Delaire, O. [Neutron Scattering Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831 (United States); Tang, X.; Lin, J. Y. Y.; Fultz, B. [California Institute of Technology, W. M. Keck Laboratory 138-78, Pasadena, California 91125 (United States)

2012-01-15T23:59:59.000Z

149

Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source  

Science Conference Proceedings (OSTI)

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically-focused neutron guide, high speed magnetic bearing choppers and a massive array of 3He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program, and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

Abernathy, Douglas L [ORNL; Stone, Matthew B [ORNL; Loguillo, Mark [ORNL; Lucas, Matthew [Air Force Research Laboratory, Wright-Patterson AFB, OH; Delaire, Olivier A [ORNL; Tang, Xiaoli [California Institute of Technology, Pasadena; Lin, J. Y. Y. [California Institute of Technology, Pasadena; Fultz, B. [California Institute of Technology, Pasadena

2012-01-01T23:59:59.000Z

150

Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma  

Science Conference Proceedings (OSTI)

During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

Ribic, B.; DebRoy, T. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Burgardt, P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2011-04-15T23:59:59.000Z

151

Emission spectra analysis of arc plasma for synthesis of carbon nanostructures in various magnetic conditions  

SciTech Connect

Arc discharge supported by the erosion of anode materials is one of the most practical and efficient methods to synthesize various high-quality carbon nanostructures. By introducing a non-uniform magnetic field in arc plasmas, high-purity single-walled carbon nanotubes (SWCNT) and large-scale graphene flakes can be obtained in a single step. In this paper, ultraviolet-visible emission spectra of arc in different spots under various magnetic conditions are analyzed to provide an in situ investigation for transformation processes of evaporated species and growth of carbon nanostructures in arc. Based on the arc spectra of carbon diatomic Swan bands, vibrational temperature in arc is determined. The vibrational temperature in arc center was measured around 6950 K, which is in good agreement with our simulation results. Experimental and simulation results suggest that SWCNT are formed in the arc periphery region. Transmission electronic microscope and Raman spectroscope are also employed to characterize the properties of carbon nanostructures.

Li Jian; Kundrapu, Madhusudhan; Shashurin, Alexey; Keidar, Michael [Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052 (United States)

2012-07-15T23:59:59.000Z

152

Proposal of an Arc Detection Technique Based on RF Measurements for the ITER ICRF Antenna  

SciTech Connect

RF arc detection is a key operational and safety issue for the ICRF system on ITER. Indeed the high voltages inside the antenna put it at risk of arcing, which could cause substantial damage. This paper describes the various possibilities explored by circuit simulation and the strategy now considered to protect the ITER ICRF antenna from RF arcs.

Huygen, S.; Dumortier, P.; Durodie, F.; Messiaen, A.; Vervier, M.; Vrancken, M. [LPP/ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Wooldridge, E. [EURATOM/CCFE Fusion Association, Culham Science Centre (United Kingdom)

2011-12-23T23:59:59.000Z

153

An optimal coarse-grained arc consistency algorithm  

Science Conference Proceedings (OSTI)

The use of constraint propagation is the main feature of any constraint solver. It is thus of prime importance to manage the propagation in an efficient and effective fashion. There are two classes of propagation algorithms for general constraints: fine-grained ... Keywords: Arc consistency, Constraint networks, Constraint programming systems, Non-binary constraints, Path consistency

Christian Bessière; Jean-Charles Régin; Roland H. C. Yap; Yuanlin Zhang

2005-07-01T23:59:59.000Z

154

PYROLYSIS OF METHANE IN A SUPERSONIC, ARC-HEATED FLOW  

E-Print Network (OSTI)

arc pyrolysis of methane at supersonic conditions, representative of conditions in the reformer is then reformed or cracked to produce hydrogen. The hy- drocarbon of choice is methane because of its highest material instead of as a fuel. Amongst various hydrogen production technologies,7 steam reformation

Texas at Arlington, University of

155

Pulse thermal processing of functional materials using directed plasma arc  

DOE Patents (OSTI)

A method of thermally processing a material includes exposing the material to at least one pulse of infrared light emitted from a directed plasma arc to thermally process the material, the pulse having a duration of no more than 10 s.

Ott, Ronald D. (Knoxville, TN); Blue, Craig A. (Knoxville, TN); Dudney, Nancy J. (Knoxville, TN); Harper, David C. (Kingston, TN)

2007-05-22T23:59:59.000Z

156

Modern Control Strategies for Vacuum Arc Remelting of Segregation ...  

Science Conference Proceedings (OSTI)

variable becomes too large, the arc will search for a less resistive path to ground ... process can enter a mode where T,, remains constant as g, opens. ... term (-20 minutes) averaging; however, this causes the system to be highly damped and.

157

A filtered cathodic arc deposition apparatus and method  

DOE Patents (OSTI)

A filtered cathodic arc deposition method and apparatus are described for the production of highly dense, wear resistant coatings which are free from macro particles. The filtered cathodic arc deposition apparatus includes a cross shaped vacuum chamber which houses a cathode target having an evaporable surface comprised of the coating material, means for generating a stream of plasma, means for generating a transverse magnetic field, and a macro particle deflector. The transverse magnetic field bends the generated stream of plasma in the direction of a substrate. Macro particles are effectively filtered from the stream of plasma by traveling, unaffected by the transverse magnetic field, along the initial path of the plasma stream to a macro particle deflector. The macro particle deflector has a preformed surface which deflects macro particles away from the substrate.

Krauss, Alan R.

1997-12-01T23:59:59.000Z

158

Plasma Arc Technology Dedicated to Solving Military Waste Problems  

E-Print Network (OSTI)

A thermal plasma is an electrically conductive gas capable of generating temperatures up to 10,000°C near its column. The energy generated by plasma arcs has recently been applied to hazardous waste disposal. Since 1989 the US Army Corps of Engineers Construction Engineering Research Laboratories have been active participants in research and development toward establishing plasma arc technology (PAT) as an efficient, economical and safe hazardous waste immobilization tool. In the U.S. the removal and disposal of asbestos contaminated material (ACM) generate significant amounts of hazardous waste. Recently, PAT has been used to convert ACM safely and efficiently into an innocuous ceramic substance no longer requiring Class I disposal. In addition to ACM waste disposal, PAT meets the waste disposal needs of pyrotechnic smoke assemblies, thermal batteries, proximity fuses, and contaminated soil. This paper will provide an overview of PAT and discuss Army and Department of Defense hazardous waste disposal needs.

Smith, E. D.; Zaghloul, H. H.

1997-04-01T23:59:59.000Z

159

Properties of vacuum arc deposited amorphous hard carbon films  

Science Conference Proceedings (OSTI)

Amorphous hard carbon films formed by vacuum arc deposition are hydrogen-free, dense, and very hard. The properties of amorphous hard carbon films depend strongly on the energy of the incident ions. A technique which is called Plasma Immersion Ion Implantation can be applied to vacuum arc deposition of amorphous hard carbon films to influence the ion energy. The authors have studied the influence of the ion energy on the elastic modulus determined by an ultrasonic method, and have measured the optical gap for films with the highest sp{sup 3} content they have obtained so far with this deposition technique. The results show an elastic modulus close to that of diamond, and an optical gap of 2.1 eV which is much greater than for amorphous hard carbon films deposited by other techniques.

Anders, S.; Anders, A.; Raoux, S. [Lawrence Berkeley Lab., CA (United States)] [and others

1995-04-01T23:59:59.000Z

160

METHOD OF OBTAINING AN IMPROVED WELD IN INERT ARC WELDING  

DOE Patents (OSTI)

A method is reported for inert arc welding. An a-c welding current is applied to the workpiece and welding electrode such that the positive portion of each cycle thereof, with the electrode positive, has only sufficient energy to clean the surface of the workpiece and the negative portion of each cycle thereof, with the electrode negative, contains the energy required to weld. (AEC)

Correy, T.B.

1962-12-11T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

SCI-Arc/Caltech Solar Decathlon 2011 Project Manual  

NLE Websites -- All DOE Office Websites (Extended Search)

CHIP CHIP 2 011 SCI---ARC / C altech S olar D ecathlon 2 011 As---Built P roject M anual 1 D.O.E. S olar D ecathlon 2 011 U.S. DEPARTMENT OF ENERGY SOLAR DECATHLON 2011 Team SCI-Arc/Caltech CHIP COMPACT HYPER_INSULATED PROTOTYPE Project Manual August 11,2011 Project Manager (Design and Construction): Reed Finlay (reed_finlay@sciarc.edu) Project Manager (PR and Development): Elisabeth Neigert (elisabeth_neigert@sciarc.edu) CHIP 2 011 SCI---ARC / C altech S olar D ecathlon 2 011 As---Built P roject M anual 2 D.O.E. S olar D ecathlon 2 011 Table o f C ontents Summary o f C hanges 2 Rules C ompliance C hecklist 3 Structural C alculations 6 Detailed W ater B udget 7 Summary o f U nlisted E lectrical C omponents 9 Summary o f R econfigurable F eatures 10 Interconnection A pplication F orm 11 Energy A nalysis R esults a nd D iscussion

162

A Glove Box Enclosed Gas-Tungsten Arc Welding System  

SciTech Connect

This report describes an inert atmosphere enclosed gas-tungsten arc welding system which has been assembled in support of the MC2730, MC2730A and MC 3500 Radioisotope Thermoelectric Generator (RTG) Enhanced Surveillance Program. One goal of this program is to fabricate welds with microstructures and impurity levels which are similar to production heat source welds previously produced at Los Alamos National Laboratory and the Mound Facility. These welds will subsequently be used for high temperature creep testing as part of the overall component lifetime assessment. In order to maximize the utility of the welding system, means for local control of the arc atmosphere have been incorporated and a wide range of welding environments can easily be evaluated. The gas-tungsten arc welding system used in the assembly is computer controlled, includes two-axis and rotary motion, and can be operated in either continuous or pulsed modes. The system can therefore be used for detailed research studies of welding impurity effects, development of prototype weld schedules, or to mimic a significant range of production-like welding conditions. Fixturing for fabrication of high temperature creep test samples have been designed and constructed, and weld schedules for grip-tab and test welds have been developed. The microstructure of these welds have been evaluated and are consistent with those used during RTG production.

Reevr, E, M; Robino, C.V.

1999-07-01T23:59:59.000Z

163

Dynamic CSPs for Interval-Based Temporal Reasoning  

Science Conference Proceedings (OSTI)

Many applications such as planning, scheduling, computational linguistics and computational models for molecular biology involve systems capable of managing qualitative and metric time information. An important issue in designing such systems is the ... Keywords: dynamic arc consistency, planning, scheduling, temporal reasoning

Malek Mouhoub; Jonathan Yip

2002-06-01T23:59:59.000Z

164

Atomic Scale Analysis of Nanostructures and Interfaces in ...  

Science Conference Proceedings (OSTI)

In our work we apply advanced transmission electron microscopy techniques to ... Robust Isothermal Electric Control of Exchange Bias Aat Room Temperature.

165

Atomic-scale Characterization of Grain Boundary Embrittlement in ...  

Science Conference Proceedings (OSTI)

The present study was performed determine the grain boundary chemistry in .... Creep of Service-Exposed SUS 316 HTB Superheater Tubes of Fossil Boilers.

166

Investigating High-TC Superconductivity on the Atomic Scale  

E-Print Network (OSTI)

Review Procedures for the storage and digestion of natural waters for the determination for the measurement of ®lterable and total phosphorus is given. Procedures reported in the literature for the storage or refrigeration (1±58C) with a preservative is suitable only for short term storage (days- months). If water

Davis, James C.

167

Skipping Atomic-scale Stones to Study Some Chemistry ...  

Science Conference Proceedings (OSTI)

... a useful stand-in for liquids, which are ... In addition, Nesbitt says, observing how gas molecules of ... how that roughness affects interactions with gases. ...

2011-05-02T23:59:59.000Z

168

How a Twinning Interface Propagate? Materials'Atomic Scale ...  

Science Conference Proceedings (OSTI)

N11: Microbilogically Influenced Corrosion of Pipeline Steels used in Oil & Gas Industry ... N2: Fabrication of Uranium Dispersion Targets for Mo-99 Production ... Numerical Modelling for Characterising the Flammability of Natural Fibre ...

169

Atomic Scale Investigation on Precipitates in High Carbon Bearing ...  

Science Conference Proceedings (OSTI)

3 Dimensional Atom Probe analyses show concentration and distribution of ... The Effects of Nb and V Microalloying on Hardenability and Age Hardening in ...

170

The Computational Modeling of Alloys at the Atomic scale  

Science Conference Proceedings (OSTI)

Different expressions for the embedding energies, densities, and pair potentials englobe a large diversity of similar models. From Equation 5 it appears clearly ...

171

Extreme Irradiation Tolerant Materials via Atomic Scale Design of ...  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking Susceptibility Assessment of AP 1000 Reactor Coolant Pump Flywheel Retainer Ring A289 18Cr-18Mn Steel by Slow Strain ...

172

Atomic Scale Imaging of Nanoscale Structures with Elemental ...  

Science Conference Proceedings (OSTI)

... for these materials, careful measurement of the position and identity of the various constituent atoms becomes essential. ... mml. Facilities/Tools Used: ...

2012-10-02T23:59:59.000Z

173

Low Power Laser Hybrid Gas Metal Arc Welding on A36 Steel  

Science Conference Proceedings (OSTI)

Presentation Title, Low Power Laser Hybrid Gas Metal Arc Welding on A36 Steel. Author(s), Caleb Roepke, Stephen Liu, Shawn Kelly, Rich Martukanitz. On-Site ...

174

Voltage Node Arcing in the ICRH Antenna Vacuum Transmission Lines at JET  

Science Conference Proceedings (OSTI)

The observation of parasitic low-VSWR activity during operations of JET RF plant and the damage caused by arcing at the voltage-node in the vacuum transmission line (VTL) in 2004 highlight the importance of the problem of low-voltage breakdown in the ICRH systems. Simulations demonstrate little response of the RF circuit to the voltage-node arcing which explains why it remains largely unnoticed and complicates the design of protection systems. Analysis of the damage pattern produced by the voltage-node arcing suggests that multipactor-related phenomena occurring at elevated voltage thresholds in conditions of unfavorable VTL geometry are most plausible arc-provoking factors.

Monakhov, I.; Graham, M.; Mayoral, M.-L.; Nicholls, K.; Walden, A. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Bobkov, V. [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2007-09-28T23:59:59.000Z

175

Pulse Thermal Processing of Functional Materials Using a Directed Plasma Arc  

Using pulses of high density infrared light from a directed plasma arc, ORNL researchersinvented a method to thermally process thin films and other ...

176

Feature based cost and carbon emission modelling for wire and arc additive manufacturing.  

E-Print Network (OSTI)

??The wire and arc additive manufacturing (WAAM) is a CNC and welding deposition based additive manufacturing method. This novel manufacturing technique has potential cost and… (more)

Guo, Jianing

2012-01-01T23:59:59.000Z

177

Formation of metal oxides by cathodic arc deposition  

DOE Green Energy (OSTI)

Metal oxide thin films are of interest for a number of applications. Cathodic arc deposition, an established, industrially applied technique for formation of nitrides (e.g. TiN), can also be used for metal oxide thin film formation. A cathodic arc plasma source with desired cathode material is operated in an oxygen atmosphere, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on ALS components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Tantalum oxide films are of interest for replacing polymer electrolytes. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/AI{sub 2}O{sub 3}/Si as possible basic structures for passive optoelectronic integrated circuits, and Al{sub 2-x}Er{sub x}O{sub 3} thin films with a variable Er concentration which is a potential component layer for the production of active optoelectronic integrated devices such as amplifiers or lasers at a wavelength of 1.53 {mu}m. Aluminum and chromium oxide films have been deposited on a number of substrates to impart improved corrosion resistance at high temperature. Titanium sub-oxides which are electrically conductive and corrosion resistant and stable in a number of aggressive environments have been deposited on various substrates. These sub-oxides are of great interest for use in electrochemical cells.

Anders, S.; Anders, A.; Rubin, M.; Wang, Z.; Raoux, S.; Kong, F.; Brown, I.G.

1995-03-01T23:59:59.000Z

178

A dimensionless parameter model for arc welding processes  

SciTech Connect

A dimensionless parameter model previously developed for C0{sub 2} laser beam welding has been shown to be applicable to GTAW and PAW autogenous arc welding processes. The model facilitates estimates of weld size, power, and speed based on knowledge of the material`s thermal properties. The dimensionless parameters can also be used to estimate the melting efficiency, which eases development of weld schedules with lower heat input to the weldment. The mathematical relationship between the dimensionless parameters in the model has been shown to be dependent on the heat flow geometry in the weldment.

Fuerschbach, P.W.

1994-12-31T23:59:59.000Z

179

Evaluation of Cracks in ABB HK Arc Chutes  

Science Conference Proceedings (OSTI)

The nuclear power industry has a number of medium voltage (5 Kv-15 Kv) ABB HK air-magnetic circuit breakers with cracks in various places on the ceramic liner plate and cold-molded asbestos portions of the arc chutes. These cracks may or may not be cosmetic. This "jump gap crack" issue has been discussed in several ABB circuit breaker users group meetings. Five utilities (Brunswick, Seabrook, TVA, Duke, and Vogtle) have previously expressed interest in this issue. The present ABB Quality Assurance Proced...

2005-05-03T23:59:59.000Z

180

Field-driven Polarization and Domain Dynamics of Ferroelectric...  

NLE Websites -- All DOE Office Websites (Extended Search)

Room 137-226 Paul G. Evans, Materials Science and Engineering, University of Wisconsin-Madison The atomic-scale periodicity of ferroelectricdielectric superlattices leads...

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin ...  

Science Conference Proceedings (OSTI)

What Can we Learn from Atomic Scale Calculations of Grain Boundary Properties? What Can We Learn from Measurements of Li-ion Battery Single Particles?

182

Underwater cladding with laser beam and plasma arc welding  

SciTech Connect

Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses.

White, R.A.; Fusaro, R.; Jones, M.G.; Solomon, H.D. [General Electric Corporate Research and Development Center, Schenectady, NY (United States); Milian-Rodriguez, R.R. [GE Nuclear Energy, San Jose, CA (United States)

1997-01-01T23:59:59.000Z

183

Thermal Treatment of Solid Wastes Using the Electric Arc Furnace  

Science Conference Proceedings (OSTI)

A thermal waste treatment facility has been developed at the Albany Research Center (ARC) over the past seven years to process a wide range of heterogeneous mixed wastes, on a scale of 227 to 907 kg/h (500 to 2,000 lb/h). The current system includes a continuous feed system, a 3-phase AC, 0.8 MW graphite electrode arc furnace, and a dedicated air pollution control system (APCS) which includes a close-coupled thermal oxidizer, spray cooler, baghouse, and wet scrubber. The versatility of the complete system has been demonstrated during 5 continuous melting campaigns, ranging from 11 to 25 mt (12 to 28 st) of treated wastes per campaign, which were conducted on waste materials such as (a) municipal incinerator ash, (b) simulated low-level radioactive, high combustible-bearing mixed wastes, (c) simulated low-level radioactive liquid tank wastes, (d) heavy metal contaminated soils, and (e) organic-contaminated dredging spoils. In all cases, the glass or slag products readily passed the U.S. Environmental Protection Agency (EPA) Toxicity Characteristic Leachability Program (TCLP) test. Additional studies are currently under way on electric utility wastes, steel and aluminum industry wastes, as well as zinc smelter residues. Thermal treatment of these solid waste streams is intended to produce a metallic product along with nonhazardous glass or slag products.

O'Connor, W.K.; Turner, P.C.

1999-09-01T23:59:59.000Z

184

NOREM Applications Guidelines: Procedures for Gas Tungsten Arc and Plasma Transferred Arc Welding of NOREM Cobalt-Free Hardfacing Al loys  

Science Conference Proceedings (OSTI)

Wire products have been successfully fabricated and new procedures developed for machine and manual gas tungsten arc welding (GTAW) of the iron-base NOREM hardfacing alloys. These developments enhance the attractiveness of NOREM alloys both in replacement valves and in field repairs of installed valves. This report describes the GTAW procedures and summarizes plasma transferred arc welding (PTAW) parameters for shop applications of NOREM alloys.

1996-01-03T23:59:59.000Z

185

Carbon nanotubes and other fullerenes produced from tire powder injected into an electric arc  

Science Conference Proceedings (OSTI)

A novel method of growing multiwall carbon nanotubes by injecting tire powder into an electric arc has been developed. The process is optimized using a DC electric arc in pressurized helium. The multiwall carbon nanotube product and the optimization process are characterized by transmission electron microscopy.

Murr, L.E. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States)]. E-mail: fekberg@utep.edu; Brown, D.K. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Esquivel, E.V. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Ponda, T.D. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Martinez, F. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Virgen, A. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States)

2005-11-15T23:59:59.000Z

186

Visual-based Intelligent Control System for Robotic Gas Metal Arc Welding  

Science Conference Proceedings (OSTI)

Sensing and control the weld pool is a crucial problem for robotic gas-metal arc welding (GMAW) process. In present research, a special vision sensing system, assisted by a narrow-band filter which could overcome the influence of the strong arc light ...

Shi Yu; Xue Cheng; Fan Ding; Chen Jianhong

2009-05-01T23:59:59.000Z

187

Simulation of the flicker phenomenon based on modeling the electric arc  

Science Conference Proceedings (OSTI)

The Electric Arc Furnace (EAF) is a very large power load, determining the negative effects on the power quality like flicker effect, harmonics currents, and reactive power. These effects are due to the nonlinear characteristic of the electric arc. In ... Keywords: flicker, harmonics, interharmonics, power quality, simulation and modeling

Manuela Panoiu; Caius Panoiu; Ioan Sora; Raluca Rob

2008-10-01T23:59:59.000Z

188

ArcMine: A GIS extension to support mine reclamation planning  

Science Conference Proceedings (OSTI)

This paper presents a new GIS extension, named ArcMine, developed to support reclamation planning in abandoned mining areas. ArcMine provides four tools to (a) assess mine subsidence hazards, (b) estimate the erosion of mine wastes, (c) analyze flow ... Keywords: GIS, Mine reclamation, Mine wastes, Mine water, Reforestation, Subsidence

Sung-Min Kim; Yosoon Choi; Jangwon Suh; Sungchan Oh; Hyeong-Dong Park; Suk-Ho Yoon; Wa-Ra Go

2012-09-01T23:59:59.000Z

189

Thermionic energy conversion research analysis. Annual progress report. [Study on plasma arc-drop  

DOE Green Energy (OSTI)

This progress report summarizes the major results presented in ''Preliminary Report on Plasma Arc-Drop in Thermionic Energy Converters,'' (COO-2533-1), and includes additional discussions on the magnitude of the normalized plasma resistance required to achieve low arc-drop converter operation.

Lam, S.H.

1976-01-01T23:59:59.000Z

190

Oxidation behavior of arc evaporated Al-Cr-Si-N thin films  

SciTech Connect

The impact of Al and Si on the oxidation behavior of Al-Cr-(Si)-N thin films synthesized by arc evaporation of powder metallurgically prepared Al{sub x}Cr{sub 1-x} targets with x = Al/(Al + Cr) of 0.5, 0.6, and 0.7 and (Al{sub 0.5}Cr{sub 0.5}){sub 1-z}Si{sub z} targets with Si contents of z = 0.05, 0.1, and 0.2 in N{sub 2} atmosphere was studied in detail by means of differential scanning calorimetry, thermogravimetric analysis (TGA), x-ray diffraction, and Raman spectroscopy. Dynamical measurements in synthetic air (up to 1440 Degree-Sign C) revealed the highest onset temperature of pronounced oxidation for nitride coatings prepared from the Al{sub 0.4}Cr{sub 0.4}Si{sub 0.2} target. Isothermal TGA at 1100, 1200, 1250, and 1300 Degree-Sign C highlight the pronounced improvement of the oxidation resistance of Al{sub x}Cr{sub 1-x}N coatings by the addition of Si. The results show that Si promotes the formation of a dense coating morphology as well as a dense oxide scale when exposed to air.

Tritremmel, Christian; Daniel, Rostislav; Mitterer, Christian; Mayrhofer, Paul H.; Lechthaler, Markus; Polcik, Peter [Christian Doppler Laboratory for Advanced Hard Coatings, Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Christian Doppler Laboratory for Application Oriented Coating Development, Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); OC Oerlikon Balzers AG, Iramali 18, LI-9496 Balzers (Liechtenstein); PLANSEE Composite Materials GmbH, Siebenbuergerstrasse 23, D-86983 Lechbruck am See (Germany)

2012-11-15T23:59:59.000Z

191

Puzzling differences in bismuth and lead plasmas: evidence for the significant role of neutrals in cathodic vacuum arcs  

E-Print Network (OSTI)

ionization energy (eV) Electrical resistivity, (n? m) @ 20°Crod, the given electrical resistivity, and an arc current of

Anders, Andre; Yushkov, Georgy Yu.

2007-01-01T23:59:59.000Z

192

Shielding of mirror FERF plasma by arc discharges  

SciTech Connect

The feasibility of shielding a mirror-confined fusion plasma against erosion by incident neutrals with a plasma blanket generated by an array of hollow-cathode arc discharges was studied. Such a plasma blanket could also be used for linetying stabilization of a single mirror confined plasma as well as to provide a warm plasma stream for stabilization of microinstabilities. The requirements for the plasma blanket are dependent on the parameter ..gamma.., the ratio of the actual cross-field diffusion coefficient to the classical value. The power requirement compares favorably with power loss due to change exchange without shielding. More importantly, the blanket permits a relaxation of vacuum requirements to prevent erosion of the hot plasma by background neutrals.

Woo, J.T.

1976-12-08T23:59:59.000Z

193

Gas-tungsten arc welding of aluminum alloys  

SciTech Connect

A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

Frye, Lowell D. (Kingston, TN)

1984-01-01T23:59:59.000Z

194

Gas-tungsten arc welding of aluminum alloys  

DOE Patents (OSTI)

The present invention is directed to a gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to profice a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surface are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy continguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

Frye, L.D.

1982-03-25T23:59:59.000Z

195

Filtered cathodic arc deposition with ion-species-selectivebias  

SciTech Connect

A dual-cathode arc plasma source was combined with acomputer-controlled bias amplifier such as to synchronize substrate biaswith the pulsed production of plasma. In this way, bias can be applied ina material-selective way. The principle has been applied to the synthesismetal-doped diamond-like carbon films, where the bias was applied andadjusted when the carbon plasma was condensing, and the substrate was atground when the metal was incorporated. In doing so, excessive sputteringby too-energetic metal ions can be avoided while the sp3/sp2 ratio can beadjusted. It is shown that the resistivity of the film can be tuned bythis species-selective bias. The principle can be extended tomultiple-material plasma sources and complex materials

Anders, Andre; Pasaja, Nitisak; Sansongsiri, Sakon; Lim, SunnieH.N.

2006-10-05T23:59:59.000Z

196

Method of operating a centrifugal plasma arc furnace  

DOE Patents (OSTI)

A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe{sub 3}O{sub 4}. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe{sub 2}O{sub 3}. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater. 3 figs.

Kujawa, S.T.; Battleson, D.M.; Rademacher, E.L. Jr.; Cashell, P.V.; Filius, K.D.; Flannery, P.A.; Whitworth, C.G.

1998-03-24T23:59:59.000Z

197

Static Heat Loads in the LHC Arc Cryostats: Final Assessment  

E-Print Network (OSTI)

This note presents the final assessment of the static heat loads in the LHC arc cryostats, using different experimental methods during the first commissioning period in 2007. This assessment further develops and completes previous estimates made during the commissioning of sector 7_8 [1]. The estimate of the helium inventory, a prerequisite for the heat load calculation, is also presented. Heat loads to the cold mass are evaluated from the internal energy balance during natural as well as powered warm-ups of the helium baths in different subsector. The helium inventory is calculated from the internal energy balance during powered warm-ups and matched with previous assessments. Furthermore, heat loads to the thermal shield are estimated from the non-isothermal cooling of the supercritical helium in line E. The comparison of measured heat loads with previous estimates and with budgeted values is then presented, while their correlation with some important parameters like insulation vacuum pressure and some heat ...

Parma, V

2010-01-01T23:59:59.000Z

198

Biological Optimization in Volumetric Modulated Arc Radiotherapy for Prostate Carcinoma  

SciTech Connect

Purpose: To investigate the potential benefits achievable with biological optimization for modulated volumetric arc (VMAT) treatments of prostate carcinoma. Methods and Materials: Fifteen prostate patient plans were studied retrospectively. For each case, planning target volume, rectum, and bladder were considered. Three optimization schemes were used: dose-volume histogram (DVH) based, generalized equivalent uniform dose (gEUD) based, and mixed DVH/gEUD based. For each scheme, a single or dual 6-MV, 356 Degree-Sign VMAT arc was used. The plans were optimized with Pinnacle{sup 3} (v. 9.0 beta) treatment planning system. For each patient, the optimized dose distributions were normalized to deliver the same prescription dose. The quality of the plans was evaluated by dose indices (DIs) and gEUDs for rectum and bladder. The tallied DIs were D{sub 1%}, D{sub 15%}, D{sub 25%}, and D{sub 40%}, and the tallied gEUDs were for a values of 1 and 6. Statistical tests were used to quantify the magnitude and the significance of the observed differences. Monitor units and treatment times for each optimization scheme were also assessed. Results: All optimization schemes generated clinically acceptable plans. The statistical tests indicated that biological optimization yielded increased organs-at-risk sparing, ranging from {approx}1% to more than {approx}27% depending on the tallied DI, gEUD, and anatomical structure. The increased sparing was at the expense of longer treatment times and increased number of monitor units. Conclusions: Biological optimization can significantly increase the organs-at-risk sparing in VMAT optimization for prostate carcinoma. In some particular cases, however, the DVH-based optimization resulted in superior treatment plans.

Mihaylov, Ivaylo B., E-mail: imihaylov@Lifespan.org [Department of Radiation Oncology, Rhode Island Hospital/Brown Medical Center, Providence, RI (United States); Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AK (United States); Fatyga, Mirek [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298 (United States); Bzdusek, Karl [Philips Radiation Oncology Systems, Fitchburg, WI (United States); Gardner, Kenneth; Moros, Eduardo G. [Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AK (United States)

2012-03-01T23:59:59.000Z

199

Exact Algorithms for Arc and Node Routing Problems  

E-Print Network (OSTI)

Oct 8, 2013 ... For both problems, there are a set of customers spread over a given graph, ... the total number of labels used during the dynamic programming.

200

Overview of magnetic nonlinear beam dynamics in the RHIC  

SciTech Connect

In this article we review our studies of nonlinear beam dynamics due to the nonlinear magnetic field errors in the Relativistic Heavy Ion Collider (RHIC). Nonlinear magnetic field errors, including magnetic field errors in interaction regions (IRs), chromatic sextupoles, and sextupole components from arc main dipoles are discussed. Their effects on beam dynamics and beam dynamic aperture are evaluated. The online methods to measure and correct the IR nonlinear field errors, second order chromaticities, and horizontal third order resonance are presented. The overall strategy for nonlinear corrections in RHIC is discussed.

Luo,Y.; Bai, M.; Beebe-Wang, J.; Bengtsson, J.; Calaga, R.; Fischer, W.; Jain, A.; Pilat, f.; Ptitsyn, V.; Malitsky, N.; Robert-Demolaize, g.; Satogata, T.; Tepikian, S.; Tomas, R.; Trbojevic, D.

2009-05-04T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

238U Decay Series Systematics Of Young Lavas From Batur Volcano, Sunda Arc  

Open Energy Info (EERE)

238U Decay Series Systematics Of Young Lavas From Batur Volcano, Sunda Arc 238U Decay Series Systematics Of Young Lavas From Batur Volcano, Sunda Arc Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: 238U Decay Series Systematics Of Young Lavas From Batur Volcano, Sunda Arc Details Activities (0) Areas (0) Regions (0) Abstract: Activities of 238U decay series radioisotopes have been determined for both postcaldera basalts erupted between 1849 and 1974 and genetically related young precaldera dacites from Batur volcano, Bali, Sunda arc. All rocks possess (230Th/238U) = 1 within 2 sigma error indicating that little, if any, fractionation between Th and U occurred during their genesis, or in their source regions, within approximately the last 350 ka. Both the basaltic and the dacitic rocks possess (230Th/232U) ~

202

An Archean Oceanic Felsic Dyke Swarm In A Nascent Arc- The Hunter Mine  

Open Energy Info (EERE)

Oceanic Felsic Dyke Swarm In A Nascent Arc- The Hunter Mine Oceanic Felsic Dyke Swarm In A Nascent Arc- The Hunter Mine Group, Abitibi Greenstone Belt, Canada Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Archean Oceanic Felsic Dyke Swarm In A Nascent Arc- The Hunter Mine Group, Abitibi Greenstone Belt, Canada Details Activities (0) Areas (0) Regions (0) Abstract: The 2730-Ma-old Hunter Mine Group (HMG), a dominantly felsic subaqueous volcanic sequence, was formed during early arc construction in the Abitibi greenstone belt (Quebec, Canada). The western part of the HMG contains a felsic dyke swarm up to 1.5 km wide and traceable up-section for 2.5 km. Five distinct generations were identified: (1) aphanitic to feldspar-phyric dykes; (2) quartz-feldspar-phyric dykes with < 5% quartz

203

Exhaust-gas measurements from NASAs HYMETS arc jet.  

SciTech Connect

Arc-jet wind tunnels produce conditions simulating high-altitude hypersonic flight such as occurs upon entry of space craft into planetary atmospheres. They have traditionally been used to study flight in Earth's atmosphere, which consists mostly of nitrogen and oxygen. NASA is presently using arc jets to study entry into Mars' atmosphere, which consists of carbon dioxide and nitrogen. In both cases, a wide variety of chemical reactions take place among the gas constituents and with test articles placed in the flow. In support of those studies, we made measurements using a residual gas analyzer (RGA) that sampled the exhaust stream of a NASA arc jet. The experiments were conducted at the HYMETS arc jet (Hypersonic Materials Environmental Test System) located at the NASA Langley Research Center, Hampton, VA. This report describes our RGA measurements, which are intended to be used for model validation in combination with similar measurements on other systems.

Miller, Paul Albert

2010-11-01T23:59:59.000Z

204

The evolution of ion charge states in cathodic vacuum arc plasmas: a review  

Science Conference Proceedings (OSTI)

Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

Anders, Andre

2011-12-18T23:59:59.000Z

205

Carbon nanostructures production by AC arc discharge plasma process at atmospheric pressure  

Science Conference Proceedings (OSTI)

Carbon nanostructures have received much attention for a wide range of applications. In this paper, we produced carbon nanostructures by decomposition of benzene using AC arc discharge plasma process at atmospheric pressure. Discharge was carried out ...

Shenqiang Zhao; Ruoyu Hong; Zhi Luo; Haifeng Lu; Biao Yan

2011-01-01T23:59:59.000Z

206

Development of an ArcGIS-pollutant load application (PLOAD) tool  

E-Print Network (OSTI)

Many of the findings of previous studies have indicated that there is a direct correlation between water quality and urbanization. Increasing impervious coverage typically results in a decrease in water quality. The purpose of this study was to adapt an automated tool for assessing the Pollutant Load Application (PLOAD). Created by CH2M HILL, a fullservice engineering and construction enterprise, PLOAD is a simplified GIS-based model used to calculate pollutants within a watershed. The so-called “simple method” implemented by PLOAD and discussed in this thesis has been endorsed by the EPA as a viable screening tool for National Pollutant Discharge Elimination System (NPDES) stormwater projects. This model was designed to be used with ArcView 3.3. ArcView 3.3 is a depreciated product, the capabilities of which have been replaced by ArcGIS 9.1. Using the same GIS data and tabular data required by PLOAD and custom ArcObjects scripting, a replacement, ArcGIS-PLOAD, was created. The current version of ArcGISPLOAD implements the “simple method” to calculate total pollutant load in pounds per year based on basin boundaries, precipitation in inches per year, ratio of storms producing runoff, parcel land use and parcel area, runoff coefficient for each land use, event mean pollutant concentrations for each land use. Time comparisons between the original PLOAD and the new ArcGIS-PLOAD revealed significant improvements. Both versions of PLOAD produce an intersection between the basin boundary and the land use layer. Calculations are actually done to the intersect layer. It was also found that the original PLOAD disregarded an albeit small portion of the intersection polygons. The new version does not. With the creation of ArcGIS-PLOAD, it is anticipated that it will become a small step in assist the State of Texas in improving water quality.

Young, De'Etra Jenra

2006-08-01T23:59:59.000Z

207

Low pressure arc discharge lamp apparatus with magnetic field generating means  

DOE Patents (OSTI)

A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25 C. 3 figs.

Grossman, M.W.; George, W.A.; Maya, J.

1987-10-06T23:59:59.000Z

208

DC Arc Fault Detection and Circuit Interruption Technologies for Photovoltaic Systems  

Science Conference Proceedings (OSTI)

In the United States, much like the rest of the world, rapid growth in photovoltaic (PV) systems is currently taking place. These systems are being installed in open fields, on parking structures, and on residential or commercial rooftops. Unfortunately, electrical arcing within a PV system’s DC circuits has caused some fires. DC-sourced electrical fires are difficult to extinguish if arcing originates from unprotected source circuits within a PV array. Several high-visibility structural fires ...

2013-12-20T23:59:59.000Z

209

Stainless steel submerged arc weld fusion line toughness  

SciTech Connect

This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations.

Rosenfield, A.R.; Held, P.R.; Wilkowski, G.M. [Battelle, Columbus, OH (United States)

1995-04-01T23:59:59.000Z

210

Target tracking using DMLC for volumetric modulated arc therapy: A simulation study  

SciTech Connect

Purpose: Target tracking using dynamic multileaf collimator (DMLC) is a promising approach for intrafraction motion management in radiation therapy. The purpose of this work is to develop a DMLC tracking algorithm capable of delivering volumetric-modulated arc therapy (VMAT) to the targets that experience two-dimensional (2D) rigid motion in the beam's eye view. Methods: The problem of VMAT delivery to moving targets is formulated as a control problem with constraints. The relationships between gantry speed, gantry acceleration, MLC leaf-velocity, dose rate, and target motion are derived. An iterative search algorithm is developed to find numerical solutions for efficient delivery of a specific VMAT plan to the moving target using 2D DMLC tracking. The delivery of five VMAT lung plans is simulated. The planned and delivered fluence maps in the target-reference frame are calculated and compared. Results: The simulation demonstrates that the 2D tracking algorithm is capable of delivering the VMAT plan to a moving target fast and accurately without violating the machine constraints and the integrity of the treatment plan. The average delivery time is only 29 s longer than that of no-tracking delivery, 101 versus 72 s, respectively. The fluence maps are normalized to 200 MU and the average root-mean-square error between the desired and the delivered fluence is 2.1 MU, compared to 14.8 MU for no-tracking and 3.6 MU for one-dimensional tracking. Conclusions: A locally optimal MLC tracking algorithm for VMAT delivery is proposed, aiming at shortest delivery time while maintaining treatment plan invariant. The inconsequential increase of treatment time due to DMLC tracking is clinically desirable, which makes VMAT with DMLC tracking attractive in treating moving tumors.

Sun Baozhou; Rangaraj, Dharanipathy; Papiez, Lech; Oddiraju, Swetha; Yang Deshan; Li, H. Harold [Department of Radiation Oncology, School of Medicine, Washington University, 4921 Parkview Place, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, Southwestern Medical Center, University of Texas, Dallas, Texas 75390 (United States); Department of Radiation Oncology, School of Medicine, Washington University, 4921 Parkview Place, St. Louis, Missouri 63110 (United States)

2010-12-15T23:59:59.000Z

211

Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.  

DOE Green Energy (OSTI)

Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

2012-01-01T23:59:59.000Z

212

Formation of Self-Organized Anode Patterns in Arc Discharge Simulations  

E-Print Network (OSTI)

Pattern formation and self-organization are phenomena commonly observed experimentally in diverse types of plasma systems, including atmospheric-pressure electric arc discharges. However, numerical simulations reproducing anode pattern formation in arc discharges have proven exceedingly elusive. Time-dependent three-dimensional thermodynamic nonequilibrium simulations reveal the spontaneous formation of self-organized patterns of anode attachment spots in the free-burning arc, a canonical thermal plasma flow established by a constant DC current between an axi-symmetric electrodes configuration in the absence of external forcing. The number of spots, their size, and distribution within the pattern depend on the applied total current and on the resolution of the spatial discretization, whereas the main properties of the plasma flow, such as maximum temperatures, velocity, and voltage drop, depend only on the former. The sensibility of the solution to the spatial discretization stresses the computational requirements for comprehensive arc discharge simulations. The obtained anode patterns qualitatively agree with experimental observations and confirm that the spots originate at the fringes of the arc - anode attachment. The results imply that heavy-species - electron energy equilibration, in addition to thermal instability, has a dominant role in the formation of anode spots in arc discharges.

Juan Pablo Trelles

2012-12-31T23:59:59.000Z

213

A high-power switch-mode dc power supply for dynamic loads  

SciTech Connect

High-voltage dc power supplies are often required to operate with highly dynamic loads, such as arcs. A switch-mode dc power supply can offer significant advantages over conventional thyristor-based dc power supplies under such conditions. It can quickly turn off the supply to extinguish the arc, and it can quickly recover after the arc. It has a relatively small output filter capacitance, which results in small stored energy available to the arc. A 400-kW, 50-kV switch-mode dc power supply for an electron-beam gun that exploits these advantages was designed and tested. It uses four 100-kW, current-source-type dc-dc converters with inputs in parallel and outputs in series. The dc-dc converters operate at 20 kHz in the voltage regulator part and 10 kHz in the inverter, transformer, and output rectifier part of the circuit. Insulated gate bipolar transistors (IGBTs) are used as the power switches. Special techniques are used to protect the power supply and load against arcs and hard shorts. The power supply has an efficiency of 93%, an output voltage ripple of 1%, and fast dynamic response. In addition, it is nearly one-third the size of conventional power supplies.

Shimer, D.W.; Lange, A.C. [Lawrence Livermore National Lab., CA (United States); Bombay, J.N. [Kaiser Engineers, Oakland, CA (United States)

1994-06-23T23:59:59.000Z

214

High-power laser and arc welding of thorium-doped iridium alloys  

SciTech Connect

The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

David, S.A.; Liu, C.T.

1980-05-01T23:59:59.000Z

215

High-power laser and arc welding of thorium-doped iridium alloys  

DOE Green Energy (OSTI)

The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

David, S.A.; Liu, C.T.

1980-05-01T23:59:59.000Z

216

Development of a Coating Formulation Procedure for Ni-base Shielded Metal Arc Electrodes with Varying Core Wire Composition.  

E-Print Network (OSTI)

??In order for manufacturers of shielded metal arc welding (SMAW) electrodes to stay competitive, they must be able to have flexibility in the performance of… (more)

Gaal, Brian

2012-01-01T23:59:59.000Z

217

Mo-containing tetrahedral amorphous carbon deposited by dual filtered cathodic vacuum arc with selective pulsed bias voltage  

E-Print Network (OSTI)

was found that the electrical resistivity decreases with ancathodic vacuum arc; electrical resistivity; profilometry;elastic modulus, high electrical resistivity, low friction

Pasaja, Nitisak; Sansongsiri, Sakon; Intasiri, Sawate; Vilaithong, Thiraphat; Anders, Andre

2007-01-01T23:59:59.000Z

218

ELECTRON MODEL OF A DOGBONE RLA WITH MULTI-PASS ARCS  

SciTech Connect

The design of a dogbone Recirculated Linear Accelerator, RLA, with linear-field multi-pass arcs was earlier developed [1] for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.5 MeV electron beam is injected at the middle of a 3 MeV/pass linac with two double-pass return arcs and is accelerated to 18 MeV in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to the frequency readily available at CEBAF: 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it straightforward to implement

Beard, Kevin B. [JLAB, MUONS Inc.; Roblin, Yves R. [JLAB; Morozov, Vasiliy [JLAB; Bogacz, Slawomir Alex [JLAB; Krafft, Geoffrey A. [JLAB

2012-09-01T23:59:59.000Z

219

Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators  

SciTech Connect

Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard

2012-06-01T23:59:59.000Z

220

A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and  

NLE Websites -- All DOE Office Websites (Extended Search)

A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and Graphene Particles This invention pertains to a highly effective arc-based synthesis of single wall carbon nanotubes and graphene particles using catalysts in the form of wires made from ion group alloys instead of commonly used catalyst powders. The catalyst wire can be introduced into the discharge either from the anode or cathode regions or into the inter-electrode gap. The catalyst introduction can be done automatically and controlled using feedback based on the ablation of the graphite electrode. To maintain simplicity and attractiveness for industrial applications, it is desirable that the catalyst composition be contained in a single wire alloy. No.: M-808 Inventor(s): Yevgeny Raitses

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Test plan for BWID Phase 2 electric arc melter vitrification tests  

SciTech Connect

This test plan describes the Buried Waste Integrated Demonstration (BWID), Phase 2, electric arc melter, waste treatment evaluation tests to be performed at the US Bureau of Mines (USBM) Albany Research Center. The BWID Arc Melter Vitrification Project is being conducted to evaluate and demonstrate existing industrial arc melter technology for thermally treating mixed transuranic-contaminated wastes and soils. Phase 1 baseline tests, performed during fiscal year 1993 at the USBM, were conducted on waste feeds representing incinerated buried mixed wastes and soils. In Phase 2, surrogate feeds will be processed that represent actual as-retrieved buried wastes from the Idaho National Engineering Laboratory`s Subsurface Disposal Area at the Radioactive Waste Management Complex.

Soelberg, N.R.; Turner, P.C.; Oden, L.L.; Anderson, G.L.

1994-10-01T23:59:59.000Z

222

Numerical predictions of railgun performance including the effects of ablation and arc drag  

SciTech Connect

Thermal radiation from plasma armatures in railguns may cause vaporization and partial ionization of the rail and insulator materials. This causes an increase in mass of the arc, which has an adverse effect on projectile velocity. Viscous drag on the arc also has a deleterious effect, particularly at high velocities. These loss mechanisms are modeled in the Los Alamos Railgun Estimator code. Simulations were performed and numerical results were compared with experimental data for a wide range of tests performed at the Los Alamos and Lawrence Livermore National Laboratories, the Ling Temco Vought Aerospace and Defense Company, and the Center for Electromechanics at the University of Texas at Austin. The effects of ablation and arc drag on railgun performance are discussed. Parametric studies illustrate the effects of some design parameters on projectile velocity and launcher efficiency. Some strategies for reducing the effects of ablation are proposed.

Schnurr, N.M.; Kerrisk, J.F.; Parker, J.V.

1986-01-01T23:59:59.000Z

223

Optical Analysis Of The Vacuum Arc Plasma Generated In Cup-Shape Contacts  

Science Conference Proceedings (OSTI)

In this paper are presented the results of the optical analysis on the rotating arc plasma, generated in the vacuum low voltage circuit breaker with cup-shaped contacts. An adequate experimental setup was used for single shot time and spatial resolved spectroscopy in order to analyze the evolution of the vacuum arc plasma. Different current interruption situations are correlated with plasma spectral diagnosis. The study is aimed to contribute to a better understanding of the complex phenomena that take place in the interruption process of high currents that appears in the short-circuit regime of electrical networks.

Pavelescu, G.; Gherendi, F. [National Institute for Optoelectronics, Bucharest-Magurele (Romania); Pavelescu, D. ['Politehnica' University of Bucharest, Bucharest (Romania); Dumitrescu, G.; Anghelita, P. [Electrotechnical Institute, ICPE, Bucharest (Romania)

2007-04-23T23:59:59.000Z

224

Super-radiance in the sodium resonance lines from sodium iodide arc lamps  

Science Conference Proceedings (OSTI)

Super-radiance observed within the centers of the sodium resonance D lines emitted by arc lamps containing sodium iodide as additive in a high-pressure mercury plasma environment was studied by high-resolution emission spectroscopy. The spectral radiance of these self-reversed lines including super-radiance was simulated by considering a local enhancement of the source function due to the presence of an additional source of radiation near the arc wall. Causes of this hitherto unrecognized source of radiation are given.

Karabourniotis, D. [Department of Physics, Institute of Plasma Physics, University of Crete, 71003 Heraklion (Greece); Drakakis, E. [Department of Electrical Engineering, Technological Educational Institute, Heraklion (Greece)

2010-08-09T23:59:59.000Z

225

Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc  

SciTech Connect

The Hf and Nd isotopic compositions of 71 Quaternary lavas collected from locations along the full length of the Aleutian island arc are used to constrain the sources of Aleutian magmas and to provide insight into the geochemical behavior of Nd and Hf and related elements in the Aleutian subduction-magmatic system. Isotopic compositions of Aleutian lavas fall approximately at the center of, and form a trend parallel to, the terrestrial Hf-Nd isotopic array with {var_epsilon}{sub Hf} of +12.0 to +15.5 and {var_epsilon}{sub Nd} of +6.5 to +10.5. Basalts, andesites, and dacites within volcanic centers or in nearby volcanoes generally all have similar isotopic compositions, indicating that there is little measurable effect of crustal or other lithospheric assimilation within the volcanic plumbing systems of Aleutian volcanoes. Hafnium isotopic compositions have a clear pattern of along-arc increase that is continuous from the eastern-most locations near Cold Bay to Piip Seamount in the western-most part of the arc. This pattern is interpreted to reflect a westward decrease in the subducted sediment component present in Aleutian lavas, reflecting progressively lower rates of subduction westward as well as decreasing availability of trench sediment. Binary bulk mixing models (sediment + peridotite) demonstrate that 1-2% of the Hf in Aleutian lavas is derived from subducted sediment, indicating that Hf is mobilized out of the subducted sediment with an efficiency that is similar to that of Sr, Pb and Nd. Low published solubility for Hf and Nd in aqueous subduction fluids lead us to conclude that these elements are mobilized out of the subducted component and transferred to the mantle wedge as bulk sediment or as a silicate melt. Neodymium isotopes also generally increase from east to west, but the pattern is absent in the eastern third of the arc, where the sediment flux is high and increases from east to west, due to the presence of abundant terrigenous sediment in the trench east of the Amlia Fracture Zone, which is being subducting beneath the arc at Seguam Island. Mixing trends between mantle wedge and sediment end members become flatter in Hf-Nd isotope space at locations further west along the arc, indicating that the sediment end member in the west has either higher Nd/Hf or is more radiogenic in Hf compared to Nd. This pattern is interpreted to reflect an increase in pelagic clay relative to the terrigenous subducted sedimentary component westward along the arc. Results of this study imply that Hf does not behave as a conservative element in the Aleutian subduction system, as has been proposed for some other arcs.

Yogodzinski, Gene; Vervoort, Jeffery; Brown, Shaun Tyler; Gerseny, Megan

2010-08-29T23:59:59.000Z

226

Corrosion and arc erosion in MHD channels. Quarterly progress report, July--September 1991  

DOE Green Energy (OSTI)

The objective of this task is to study the corrosion and arc erosion of MHD materials in a cooperative effort with, and to support, the MHD topping cycle program. Materials tested in the Avco Research Laboratory/Textron facility, or materials which have significant MHD importance, will be analyzed to document their physical deterioration. Conclusions shall be drawn about their wear mechanisms and lifetime in the MHD environment with respect to the following issues; sulfur corrosion, electrochemical corrosion, and arc erosion. The impact of any materials or slag conditions on the level of power output and on the level of leakage current in the MHD channel will also be noted, where appropriate.

Rosa, R.J. [Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering; Pollina, R.J. [Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering]|[Avco-Everett Research Lab., Everett, MA (United States)

1991-10-01T23:59:59.000Z

227

Impact of ArcA loss in Shewanella oneidensis revealed by comparative proteomics under aerobic and anaerobic conditions  

SciTech Connect

Shewanella inhabit a wide variety of niches in nature and can utilize a broad spectrum of electron acceptors under anaerobic conditions. How they modulate their gene expression to adapt is poorly understood. ArcA, homologue of a global regulator controlling hundreds of genes involved in aerobic and anaerobic respiration in E. coli, was shown to be important in aerobiosis/anaerobiosis of S. oneidensis as well. Loss of ArcA, in addition to altering transcription of many genes, resulted in impaired growth under aerobic condition, which was not observed in E. coli. To further characterize the impact of ArcA loss on gene expression on the level of proteome under aerobic and anaerobic conditions, liquid-chromatography-mass-spectrometry (LC-MS) based proteomic approach was employed. Results show that ArcA loss led to globally altered gene expression, generally consistent with that observed with transcripts. Comparison of transcriptomic and proteomic data permitted identification of 17 high-confidence ArcA targets. Moreover, our data indicate that ArcA is required for regulation of cytochrome c proteins, and the menaquinone level may play a role in regulating ArcA as in E. coli. Proteomic-data-guided growth assay revealed that the aerobic growth defect of ArcA mutant is presumably due to impaired peptide utilization.

Yuan, Jie; Wei, Buyun; Lipton, Mary S.; Gao, Haichun

2012-06-01T23:59:59.000Z

228

Pleistocene hinterland evolution of the active Banda Arc: Surface uplift and neotectonic deformation recorded by coral terraces at Kisar, Indonesia  

E-Print Network (OSTI)

deformation recorded by coral terraces at Kisar, Indonesia AND Hinterland emergence of the active Banda arc-continent collision: Metamorphism, geochronology, and structure of the uplifted Kisar Atoll, Indonesia and related Banda Arc: surface uplift and neotectonic deformation recorded by coral terraces at Kisar, Indonesia

Seamons, Kent E.

229

Book Review: Arc Marine -GIS For A Blue Planet on 22-09-2007 10:44  

E-Print Network (OSTI)

Book Review: Arc Marine - GIS For A Blue Planet on 22-09-2007 10:44 A few year's ago I 47.95 USD / 34.00 Euro Review by Jeff Thurston I was subsequently surprised when the new book Arc Marine: GIS for a Blue Planet arrived at my doorstep. The book includes a foreword by Jane Lubchenco

Wright, Dawn Jeannine

230

Dislocation Dynamics  

Science Conference Proceedings (OSTI)

Mar 7, 2013 ... Recent Progress in Dislocation Dynamics: Sylvie Aubry1; Athanasios Arsenlis1; Wei Cai2; Steve Fitzgerald3; 1LLNL; 2Stanford University; ...

231

Permian evolution of sandstone composition in a complex back-arc extensional to foreland basin: The Bowen Basin, eastern Australia  

SciTech Connect

The Bowen Basin is a Permo-Triassic, back-arc extensional to foreland basin that developed landward of an intermittently active continental volcanic arc associated with the eastern Australian convergent plate margin. The basin has a complex, polyphase tectonic history that began with limited back-arc crustal extension during the Early Permian. This created a series of north-trending grabens and half grabens which, in the west, accommodated quartz-rich sediment derived locally from surrounding, uplifted continental basement. In the east, coeval calc-alkaline, volcanolithic-rich, and volcaniclastic sediment was derived from the active volcanic arc. This early extensional episode was followed by a phase of passive thermal subsidence accompanied by episodic compression during the late Early Permian to early Late Permian, with little contemporaneous volcanism. In the west, quartzose sediment was shed from stable, polymictic, continental basement immediately to the west and south of the basin, whereas volcanolithic-rich sediment that entered the eastern side of the basin during this time was presumably derived from the inactive, and possibly partly submerged volcanic arc. During the late Late Permian, flexural loading and increased compression occurred along the eastern margin of the Bowen Basin, and renewed volcanism took place in the arc system to the east. Reactivation of this arc led to westward and southward spread of volcanolithic-rich sediment over the entire basin. Accordingly, areas in the west that were earlier receiving quartzose, craton-derived sediment from the west and south were overwhelmed by volcanolithic-rich, arc-derived sediment from the east and north. This transition from quartz-rich, craton-derived sediments to volcanolithic-rich, arc-derived sediments is consistent with the interpreted back-arc extensional to foreland basin origin for the Bowen Basin.

Baker, J.C. (Univ. of Queensland, (Australia). Centre for Microscopy and Microanalysis); Fielding, C.R. (Univ. of Queensland, (Australia). Dept. of Earth Sciences); Caritat, P de (Australian National Univ., Canberra (Australia). Dept. of Geology); Wilkinson, M.M. (Santos Petroleum, Queensland (Australia))

1993-09-01T23:59:59.000Z

232

Development and evaluation of GIS-based ArcPRZM-3 system for spatial modeling of groundwater vulnerability to pesticide contamination  

Science Conference Proceedings (OSTI)

The objectives of this study were to develop and evaluate a GIS-based modeling system called ArcPRZM-3 for spatial modeling of pesticide leaching potential from soil surface towards groundwater. The ArcPRZM-3 was developed by coupling a commonly used ... Keywords: ArcPRZM-3, GIS, Groundwater, Groundwater spatial modeling, PRZM-3, Pesticide, Vulnerability assessment

Tahir Ali Akbar; Henry Lin; John DeGroote

2011-07-01T23:59:59.000Z

233

(Smart) Look-Ahead Arc Consistency and the Pursuit of CSP Tractability  

E-Print Network (OSTI)

(Smart) Look-Ahead Arc Consistency and the Pursuit of CSP Tractability Hubie Chen 1 and V#19. The constraint satisfaction problem (CSP) can be formu- lated as the problem of deciding, given a pair (A; B) of relational struc- tures, whether or not there is a homomorphism from A to B. Although the CSP is in general

Dalmau, Victor

234

How do I display the Map of Wind Farms csv coordinates in ArcMap software?  

Open Energy Info (EERE)

display the Map of Wind Farms csv coordinates in ArcMap software? display the Map of Wind Farms csv coordinates in ArcMap software? Home > Groups > Geospatial I downloaded the Map of Wind Farms data as a .csv from http://en.openei.org/wiki/Map_of_Wind_Farms/Data. The downloaded data contains the latitude and longitude values in a single column. ArcMap requires separate fields for lat/long. Also, there is a strange character at the end of the coordinate values, °. It looks like this might be due to using the degree symbol? Will this cause an issue when attempting to import the downloaded data into ESRI ArcMap software? Thanks for any guidance you can provide! Submitted by Scourer on 10 September, 2013 - 09:40 1 answer Points: 1 Hi- Yes, you are correct with determining why the ° characters appear in the CSV. This is an artifact of transforming the coordinates to values for the

235

Silica-alumina trihydrate filled epoxy castings resistant to arced SF.sub.6  

SciTech Connect

A cured, insulating, casting composition, having a coefficient of linear thermal expansion of below about 38 .times. 10.sup.-6 in./in./.degree. C and being resistant to arced sulfur hexafluoride gas, in contact with a metal surface in a sulfur hexafluoride gas environment, is made from hydantoin epoxy resin, anhydride curing agent and a filler combination of fused silica and alumina trihydrate.

Chenoweth, Terrence E. (Monroeville, PA); Yeoman, Frederick A. (Murrysville, PA)

1978-01-01T23:59:59.000Z

236

A model of plasma discharges in pre-arcing regime for water treatment  

Science Conference Proceedings (OSTI)

It is presented a simulation study of a water treatment system based upon 1 kHz frequency plasma discharges in the pre-arcing regime produced within a coaxial cylinder reactor. The proposed computational model takes into consideration the three main ... Keywords: modelling, pulsed corona discharges, simulation, streamers

B. G. Rodríguez-Méndez; R. López-Callejas; R. Peña-Eguiluz; A. Mercado-Cabrera; R. Valencia-Alvarado; S. R. Barocio; A. de la Piedad-Beneitez; J. S. Benítez-Read; J. O. Pacheco-Sotelo

2006-02-01T23:59:59.000Z

237

Optimization of bead geometry of submerged arc weld using fuzzy based desirability function approach  

Science Conference Proceedings (OSTI)

The present study highlights application of Taguchi's robust design coupled with fuzzy based desirability function approach for optimizing multiple bead geometry parameters of submerged arc weldment. Fuzzy inference system has been adapted to avoid uncertainly, ... Keywords: Desirability function, Fuzzy logic, SAW, Taguchi's robust design

Ankita Singh; Saurav Datta; Siba Sankar Mahapatra; Tapan Singha; Gautam Majumdar

2013-02-01T23:59:59.000Z

238

File-Based storage of digital objects and constituent datastreams: XMLtapes and internet archive ARC files  

Science Conference Proceedings (OSTI)

This paper introduces the write-once/read-many XMLtape/ARC storage approach for Digital Objects and their constituent datastreams. The approach combines two interconnected file-based storage mechanisms that are made accessible in a protocol-based manner. ...

Xiaoming Liu; Lyudmila Balakireva; Patrick Hochstenbach; Herbert Van de Sompel

2005-09-01T23:59:59.000Z

239

Fast Arc Delivery for Stereotactic Body Radiotherapy of Vertebral and Lung Tumors  

SciTech Connect

Purpose: Flattening filter-free (FFF) beams with higher dose rates and faster delivery are now clinically available. The purpose of this planning study was to compare optimized non-FFF and FFF RapidArc plans for stereotactic body radiotherapy (SBRT) and to validate the accuracy of fast arc delivery. Methods and Material: Ten patients with peripheral lung tumors and 10 with vertebral metastases were planned using RapidArc with a flattened 6-MV photon beam and a 10-MV FFF beam for fraction doses of 7.5-18 Gy. Dosimetry of the target and organs at risk (OAR), number of monitor units (MU), and beam delivery times were assessed. GafChromic EBT2 film measurements of FFF plans were performed to compare calculated and delivered dose distributions. Results: No major dosimetric differences were seen between the two delivery techniques. For lung SBRT plans, conformity indices and OAR doses were similar, although the average MU required were higher with FFF plans. For vertebral SBRT, FFF plans provided comparable PTV coverage, with no significant differences in OAR doses. Average beam delivery times were reduced by a factor of up to 2.5, with all FFF fractions deliverable within 4 min. Measured FFF plans showed high agreement with calculated plans, with more than 99% of the area within the region of interest fulfilling the acceptance criterion. Conclusion: The higher dose rate of FFF RapidArc reduces delivery times significantly, without compromising plan quality or accuracy of dose delivery.

Ong, Chin Loon, E-mail: c.ong@vumc.nl [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands); Verbakel, Wilko F.A.R.; Dahele, Max; Cuijpers, Johan P.; Slotman, Ben J.; Senan, Suresh [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands)

2012-05-01T23:59:59.000Z

240

Arc-melting preparation of single crystal LaB.sub.6 cathodes  

DOE Patents (OSTI)

A method for preparing single crystals of lanthanum hexaboride (LaB.sub.6) by arc melting a rod of compacted LaB.sub.6 powder. The method is especially suitable for preparing single crystal LaB.sub.6 cathodes for use in scanning electron microscopes (SEM) and scanning transmission electron microscopes (STEM).

Gibson, Edwin D. (Ames, IA); Verhoeven, John D. (Ames, IA)

1977-06-21T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A model for temperature prediction of melted steel in the electric arc furnace (EAF)  

Science Conference Proceedings (OSTI)

A constant aspiration to optimize electric arc steelmaking process causes an increase of the use of advanced analytical methods for the process support. The goal of the paper is to present the way to predict temperature of melted steel in the electric ...

Marcin Blachnik; Krystian M?czka; Tadeusz Wieczorek

2010-06-01T23:59:59.000Z

242

Welding of NOREM Iron-Base Hardfacing Alloy Wire Products: Procedures for Gas Tungsten Arc Welding  

Science Conference Proceedings (OSTI)

New wire products have been successfully fabricated and procedures developed for automatic gas tungsten arc welding of wear-resistant NOREM iron-base alloys. Research demonstrated that sound multi-layer welds on carbon and stainless steel substrates can be obtained without the use of preheating. These developments point to the advantages of NOREM alloys for field applications, such as valve refurbishing.

1992-09-01T23:59:59.000Z

243

Measurement and finite element analysis of temperature distribution in arc welding process  

Science Conference Proceedings (OSTI)

This presentation describes both the experimental measurement and finite element analysis used to study the temperature distribution during a metal inert gas (MIG) welding process, including the cooling down period. Welding was carried out on ... Keywords: FEA, MIG welding, arc welding, cracking, finite element analysis, metal inert gas welding, residual stress, simulation, temperature distribution, weldment temperature

C. K. Lee; J. Candy; C. P. H. Tan

2004-12-01T23:59:59.000Z

244

How do I display the Map of Wind Farms csv coordinates in ArcMap software?  

Open Energy Info (EERE)

How do I display the Map of Wind Farms csv coordinates in ArcMap software? How do I display the Map of Wind Farms csv coordinates in ArcMap software? Home > Groups > Geospatial I downloaded the Map of Wind Farms data as a .csv from http://en.openei.org/wiki/Map_of_Wind_Farms/Data. The downloaded data contains the latitude and longitude values in a single column. ArcMap requires separate fields for lat/long. Also, there is a strange character at the end of the coordinate values, °. It looks like this might be due to using the degree symbol? Will this cause an issue when attempting to import the downloaded data into ESRI ArcMap software? Thanks for any guidance you can provide! Submitted by Scourer on 10 September, 2013 - 09:40 1 answer Points: 1 Hi- Yes, you are correct with determining why the ° characters appear in the

245

Localization of deformable tumors from short-arc projections using Bayesian estimation  

Science Conference Proceedings (OSTI)

Purpose: The authors present a stochastic framework for radiotherapy patient positioning directly utilizing radiographic projections. This framework is developed to be robust against anatomical nonrigid deformations and to cope with challenging imaging scenarios, involving only a few cone beam CT projections from short arcs. Methods: Specifically, a Bayesian estimator (BE) is explicitly derived for the given scanning geometry. This estimator is compared to reference methods such as chamfer matching (CM) and the minimization of the median absolute error adapted as tools of robust image processing and statistics. In order to show the performance of the stochastic short-arc patient positioning method, a CIRS IMRT thorax phantom study is presented with movable markers and the utilization of an Elekta Synergy{sup Registered-Sign} XVI system. Furthermore, a clinical prostate CBCT scan of a Varian{sup Registered-Sign} On-Board Imager{sup Registered-Sign} system is utilized to investigate the robustness of the method for large variations of image quality (anterior-posterior vs lateral views). Results: The results show that the BE shifts reduce the initial setup error of up to 3 cm down to 3 mm at maximum for an imaging arc as short as 10 Degree-Sign while CM achieves residual errors of 7 mm at maximum only for arcs longer than 40 Degree-Sign . Furthermore, the BE can compensate robustly for low image qualities using several low quality projections simultaneously. Conclusions: In conclusion, an estimation method for marker-based patient positioning for short imaging arcs is presented and shown to be robust and accurate for deformable anatomies.

Hoegele, W.; Zygmanski, P.; Dobler, B.; Kroiss, M.; Koelbl, O.; Loeschel, R. [Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany) and Department of Computer Science and Mathematics, University of Applied Sciences, 93053 Regensburg (Germany); Department of Radiation Oncology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States); Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany); Department of Radiation Oncology, Hospital of the Sisters of Mercy, 4010 Linz (Austria); Department of Radiation Oncology, Regensburg University Medical Center, 93053 Regensburg (Germany); Department of Computer Science and Mathematics, University of Applied Sciences, 93053 Regensburg (Germany)

2012-12-15T23:59:59.000Z

246

Verification of dose distribution for volumetric modulated arc therapy total marrow irradiation in a humanlike phantom  

SciTech Connect

Purpose: Volumetric modulated arc therapy (VMAT) treatment planning studies have been reported to provide good target coverage and organs at risk (OARs) sparing in total marrow irradiation (TMI). A comprehensive dosimetric study simulating the clinical situation as close as possible is a norm in radiotherapy before a technique can be used to treat a patient. Without such a study, it would be difficult to make a reliable and safe clinical transition especially with a technique as complicated as VMAT-TMI. To this end, the dosimetric feasibility of VMAT-TMI technique in terms of treatment planning, delivery efficiency, and the most importantly three dimensional dose distribution accuracy was investigated in this study. The VMAT-TMI dose distribution inside a humanlike Rando phantom was measured and compared to the dose calculated using RapidArc especially in the field junctions and the inhomogeneous tissues including the lungs, which is the dose-limiting organ in TMI. Methods: Three subplans with a total of nine arcs were used to treat the planning target volume (PTV), which was determined as all the bones plus the 3 mm margin. Thermoluminescent detectors (TLDs) were placed at 39 positions throughout the phantom. The measured TLD doses were compared to the calculated plan doses. Planar dose for each arc was verified using mapcheck. Results: TLD readings demonstrated accurate dose delivery, with a median dose difference of 0.5% (range: -4.3% and 6.6%) from the calculated dose in the junctions and in the inhomogeneous medium including the lungs. Conclusions: The results from this study suggest that RapidArc VMAT technique is dosimetrically accurate, safe, and efficient in delivering TMI within clinically acceptable time frame.

Surucu, Murat; Yeginer, Mete; Kavak, Gulbin O.; Fan, John; Radosevich, James A.; Aydogan, Bulent [Department of Radiation and Cellular Oncology University of Chicago, 5758 South Maryland Avenue, MC 9006, Chicago, Illinois 60637 (United States); Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, Chicago, Illinois 60612 (United States); Department of Radiation Oncology, Edwards Hospital, 801 South Washington Street, Naperville, Illinois 60540 (United States); Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, Chicago, Illinois 60612 (United States); Department of Radiation and Cellular Oncology University of Chicago, 5758 South Maryland Avenue, MC 9006, Chicago, Illinois 60637 (United States) and Department of Radiation Oncology, University of Illinois at Chicago Medical Center, 1801 West Taylor Street, C400, Chicago, Illinois 60612 (United States)

2012-01-15T23:59:59.000Z

247

Comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)  

SciTech Connect

The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

Nunes, A.C. Jr.

1985-08-01T23:59:59.000Z

248

Geochemical tracers of processes affecting the formation of seafloor hydrothermal fluids and deposits in the Manus back-arc basin  

E-Print Network (OSTI)

Systematic differences in trace element compositions (rare earth element (REE), heavy metal, metalloid concentrations) of seafloor vent fluids and related deposits from hydrothermal systems in the Manus back-arc basin ...

Craddock, Paul R

2009-01-01T23:59:59.000Z

249

Improved structural and electrical properties of thin ZnO:Al films by dc filtered cathodic arc deposition  

E-Print Network (OSTI)

that nearly the entire solar spectrum can be transmitted,and nearly the entire solar spectrum is transmitted. Thisspectrum. Therefore, arc-grown AZO is potentially suitable for high efficiency, multijunction solar

Zhu, Yuankun

2013-01-01T23:59:59.000Z

250

Evaluation Of Four Welding Arc Processes Applied To 6061 Aluminium Alloy  

Science Conference Proceedings (OSTI)

At a time when greenhouse gas emissions must be reduced, the use of the aluminium alloys is expanding, in particular in the transportation industry. In order to extend the possibilities of aluminium assembly design, new Metal Inert Gas (MIG) welding processes have been conceived. They work at lower temperatures than usual arc processes (classic MIG or Tungsten Inert Gas). This study compares four arc welding processes, applied to the 6061 aluminium alloy. These four weld processes have been studied through the metallurgical analysis of the weld beads. Metallography, micro-hardness testings, X Ray radiography have been carried out on the produced weld beads. The processes are classified according to the quality of the beads like geometry of beads, size of the heat affected zone and presence of defects.

Benoit, A. [Univ Paris-Sud, Laboratoire de Physico-Chimie de l'Etat Solide, UMR 8182, 91405 Orsay, F-91405 (France); Laboratoire de Genie des Materiaux et Procedes Associes (LGMPA), Ecole Polytechnique de l'Universite de Nantes, Nantes Atlantique Universites, rue Christian Pauc, BP 50609, 44306 Nantes Cedex 3 (France); Paillard, P. [Laboratoire de Genie des Materiaux et Procedes Associes (LGMPA), Ecole Polytechnique de l'Universite de Nantes, Nantes Atlantique Universites, rue Christian Pauc, BP 50609, 44306 Nantes Cedex 3 (France); Baudin, T. [Univ Paris-Sud, Laboratoire de Physico-Chimie de l'Etat Solide, UMR 8182, 91405 Orsay, F-91405 (France); CNRS, Orsay, F-91405 (France); Jobez, S.; Castagne, J.-F. [SNECMA-Usine d'Evry-Corbeil Snecma Evry-Corbeil-Route Henri Auguste Desbrueres-91000 Evry (France)

2011-01-17T23:59:59.000Z

251

Schlieren technique applied to the arc temperature measurement in a high energy density cutting torch  

SciTech Connect

Plasma temperature and radial density profiles of the plasma species in a high energy density cutting arc have been obtained by using a quantitative schlieren technique. A Z-type two-mirror schlieren system was used in this research. Due to its great sensibility such technique allows measuring plasma composition and temperature from the arc axis to the surrounding medium by processing the gray-level contrast values of digital schlieren images recorded at the observation plane for a given position of a transverse knife located at the exit focal plane of the system. The technique has provided a good visualization of the plasma flow emerging from the nozzle and its interactions with the surrounding medium and the anode. The obtained temperature values are in good agreement with those values previously obtained by the authors on the same torch using Langmuir probes.

Prevosto, L.; Mancinelli, B. [Departamento Ing. Electromecanica, Grupo de Descargas Electricas, Universidad Tecnologica Nacional, Regional Venado Tuerto, Las Heras 644, Venado Tuerto, Santa Fe 2600 (Argentina); Artana, G. [Departamento Ing. Mecanica, Laboratorio de Fluidodinamica, Facultad de Ingenieria (UBA), Paseo Colon 850 (C1063ACV), Buenos Aires (Argentina); Kelly, H. [Departamento de Fisica, Instituto de Fisica del Plasma (CONICET), Facultad de Ciencias Exactas y Naturales (UBA), Ciudad Universitaria Pab. I, Buenos Aires 1428 (Argentina)

2010-01-15T23:59:59.000Z

252

Bounds for the moduli of continuity for conformal mappings of domains near their accessible boundary arcs  

SciTech Connect

The paper presents bounds for the moduli of continuity {omega}(f, G-bar ,{delta}) of conformal mappings w=f(z) of a bounded simply connected domain G with an arbitrary Jordan boundary onto a bounded simply connected domain with an arbitrary Jordan boundary, the 'quality' of boundaries being taken into account. For a Jordan curve (simple arc or a closed contour), its quality is characterized in general by its modulus of oscillation, and if it has finite length, by a more sensitive modulus of rectifiability-these purely metric concepts were introduced by the author in 1996. Theorems on the behaviour of conformal mappings of simply connected domains of arbitrary nature near open accessible boundary arcs are established. Bibliography: 18 titles.

Dolzhenko, Evgenii P [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

2011-12-31T23:59:59.000Z

253

Mechanism of surface modification in the plasma-surface interaction in electrical arcs  

SciTech Connect

Electrical sparks and arcs are plasma discharges that carry large currents and can strongly modify surfaces. This damage usually comes in the form of micrometer-sized craters and frozen-in liquid on the surface. Using a combination of experiments, plasma and atomistic simulation tools, we now show that the observed formation of deep craters and liquidlike features during sparking in vacuum is explained by the impacts of energetic ions, accelerated under the given conditions in the plasma sheath to kiloelectron volt energies, on surfaces. The flux in arcs is so high that in combination with kiloelectron volt energies it produces multiple overlapping heat spikes, which can lead to cratering even in materials such as Cu, where a single heat spike normally does not.

Timko, H.; Djurabekova, F.; Nordlund, K.; Costelle, L.; Matyash, K.; Schneider, R.; Toerklep, A.; Arnau-Izquierdo, G.; Descoeudres, A.; Calatroni, S.; Taborelli, M.; Wuensch, W. [CERN, CH-1211 Geneve 23 (Switzerland); and Helsinki Institute of Physics and Department of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Helsinki Institute of Physics and Department of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Department of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); CERN, CH-1211 Geneve 23 (Switzerland)

2010-05-01T23:59:59.000Z

254

Graphene layer growth on silicon substrates with nickel film by pulse arc plasma deposition  

Science Conference Proceedings (OSTI)

Carbon layer has been grown on a Ni/SiO{sub 2}/Si(111) substrate under high vacuum pressure by pulse arc plasma deposition. From the results of Raman spectroscopy for the sample, it is found that graphene was formed by ex-situ annealing of sample grown at room temperature. Furthermore, for the sample grown at high temperature, graphene formation was shown and optimum temperature was around 1000 Degree-Sign C. Transmission electron microscopy observation of the sample suggests that the graphene was grown from step site caused by grain of Ni film. The results show that the pulse arc plasma technique has the possibility for acquiring homogenous graphene layer with controlled layer thickness.

Fujita, K.; Banno, K.; Aryal, H. R.; Egawa, T. [Research Center for Nano-Device and System, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555 (Japan)

2012-10-15T23:59:59.000Z

255

Control of Gas Tungsten Arc welding pool shape by trace element addition to the weld pool  

DOE Patents (OSTI)

An improved process for Gas Tungsten Arc welding maximizes the depth/width ratio of the weld pool by adding a sufficient amount of a surface active element to insure inward fluid flow, resulting in deep, narrow welds. The process is especially useful to eliminate variable weld penetration and shape in GTA welding of steels and stainless steels, particularly by using a sulfur-doped weld wire in a cold wire feed technique.

Heiple, C.R.; Burgardt, P.

1984-03-13T23:59:59.000Z

256

Solid oxide fuel cell processing using plasma arc spray deposition techniques. Final report  

DOE Green Energy (OSTI)

The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

Ray, E.R.; Spengler, C.J.; Herman, H.

1991-07-01T23:59:59.000Z

257

Solid oxide fuel cell processing using plasma arc spray deposition techniques  

DOE Green Energy (OSTI)

The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

Ray, E.R.; Spengler, C.J.; Herman, H.

1991-07-01T23:59:59.000Z

258

Joint TVA EPRI Evaluation of Steel Arc Furnace Regulation Impacts and Potential Innovative Mitigation Solutions: Phase I  

Science Conference Proceedings (OSTI)

The Tennessee Valley Authority (TVA) is considering the costs and benefits of serving arc furnace loads. One potential adverse power system impact of arc furnaces is that their electric power consumption is extremely volatile and can significantly impact the short-term frequency regulation requirements of the TVA power system, increasing the regulating reserve requirements needed to meet North American Electric Reliability Council (NERC) reliability criteria. A one-month analysis of TVA regulation ...

2013-12-13T23:59:59.000Z

259

Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma  

SciTech Connect

In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

Keidar, Michael [George Washington University] [George Washington University

2013-06-23T23:59:59.000Z

260

Spontaneous combustion prediction of coal by C80 and ARC techniques  

Science Conference Proceedings (OSTI)

Many coal fires were caused by spontaneous combustion in coal mines or coal storehouses, which resulted in a great loss and energy wastage. To identify and evaluate the hazardous degree of coal stockpile, a C80 microcalorimeter and accelerating rate calorimeter (ARC) were employed in this work. The coal samples undergo an exothermal process start at 80 {sup o}C with heat generation of -75.1 J g{sup -1} (mean value) detected by C80 experiment. The activation energies of the first exothermal process were calculated for the three experiments, and the mean value is 80.76 kJ mol{sup -1}, which is lower than that of obtained from the ARC result, 127.0 kJ mol{sup -1}. For a 300 tons coal stockpile, the self-heating oxidation temperatures (SHOT) were calculated as 164, 60, 90, and 68{sup o}C based on the ARC experiment and three C80 experiments, respectively. Further research on the mass effect on SHOT shows that if the coal mass is less than 12 tons, the danger of thermal spontaneous combustion is less. However, if the mass amount is more than 12000 tons, the danger of thermal spontaneous combustion is difficult to avoid even at ambient temperature if no special measures are taken. 38 refs., 9 figs.

Qingsong Wang; Song Guo; Jinhua Sun [University of Science and Technology of China, Hefei (China). State Key Laboratory of Fire Science

2009-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Consumable arc-melting, extruding, and rolling process for iridium sheet  

SciTech Connect

An iridium alloy has been used as cladding for the /sup 238/PuO/sub 2/ fuel in radioisotope thermoelectric generators (RTGs) for recent interplanetary spacecraft such as Voyagers 1 and 2 and will be used for the Galileo and Ulysses spacecraft. The iridium alloy sheet for the fuel cladding used on these missions was fabricated by hot and cold rolling of arc-melted and drop-cast 0.5-kg ingots. Upon completion of production for these spacecraft, an opportunity was taken to conduct process improvement studies that would increase processing batch sizes, develop a more uniform product, decrease rejections due to internal delaminations and surface defects, and reduce costs. The studies to scale up and improve the fabrication process are described. In the new process, iridium is electron beam melted, alloyed by arc melting, and then consumable arc melted to form a cylindrical ingot of approximately 7 kg for extrusion. The ingot is extruded to sheet bar and hot and cold rooled into sheet. Sheet evaluated from the first two ingots showed 100% acceptance with no defects on inspection. An improved uniformity of microstructure was obtained, and chemistry was controlled within specification limits.

Heestand, R.L.; Copeland, G.L.; Martin, M.M.

1986-06-01T23:59:59.000Z

262

Dynamic tariffs  

SciTech Connect

The general theoretical models of dynamic tariffs, such as spot pricing, are extended in this paper to include the issues of optimal response of industrial consumers and the effect of large scale penetration of these tariffs on the utility load curve. If such tariffs are to serve their purpose consumers need to acquire the ability for flexible and dynamic response. While the hardware for this is readily available the theoretical models and software systems are not. These issues are examined and correlated with industrial site studies. A systematic analysis of the effect of significant consumer response on the system load curve is next undertaken. A methodologically sound approach to system load and price forecasting is presented.

David, A.K.; Lee, Y.C.

1989-08-01T23:59:59.000Z

263

Formation of NOx precursors during Chinese pulverized coal pyrolysis in an arc plasma jet  

Science Conference Proceedings (OSTI)

The formation of NOx precursors (HCN and NH{sub 3}) from the pyrolysis of several Chinese pulverized coals in an arc plasma jet was investigated through both thermodynamic analysis of the C-H-O-N system and experiments. Results of thermodynamic analysis show that the dominant N-containing gaseous species is HCN together with a small amount of ammonia above the temperature of 2000 K. The increase of H content advances the formation of HCN and NH{sub 3}, but the yields of HCN and NH{sub 3} are decreased with a high concentration of O in the system. These results are accordant with the experimental data. The increasing of input power promotes the formation of HCN and NH{sub 3} from coal pyrolysis in an arc plasma jet. Tar-N is not formed during the process. The yield of HCN changes insignificantly with the changing of the residence time of coal particles in the reactor, but that of NH{sub 3} decreases as residence times increase because of the relative instability at high temperature. Adsorption and gasification of CO{sub 2} on the coal surface also can restrain the formation of HCN and NH{sub 3} compare to the results in an Ar plasma jet. Yields of HCN and NH{sub 3} are sensitive to the coal feeding rate, indicating that NOx precursors could interact with the nascent char to form other N-containing species. The formation of HCN and NH{sub 3} during coal pyrolysis in a H{sub 2}/Ar plasma jet are not dependent on coal rank. The N-containing gaseous species is released faster than others in the volatiles during coal pyrolysis in an arc plasma jet, and the final nitrogen content in the char is lower than that in the parent coal, which it is independent of coal type. 16 refs., 9 figs., 1 tab.

Wei-ren Bao; Jin-cao Zhang; Fan Li; Li-ping Chang [Taiyuan University of Technology, Taiyuan (China). Key Laboratory of Coal Science and Technology

2007-08-15T23:59:59.000Z

264

Parametric Studies Of Weld Quality Of Tungsten Inert Gas Arc Welding Of Stainless Steel  

Science Conference Proceedings (OSTI)

Effect of current and gas flow rate on quality of weld in tungsten inter gas arc welding of austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current and gas flow rate. The quality of the weld has been evaluated in terms of ultimate and breaking strengths of the welded specimens. The observed data have been interpreted, discussed and analyzed by using Grey--Taguchi methodology. Optimum parametric setting has been predicted and validated as well.

Kumar Pal, Pradip; Nandi, Goutam; Ghosh, Nabendu [Mechanical Engineering Department, Jadavpur University, Kolkata-700032 (India)

2011-01-17T23:59:59.000Z

265

Efficient Algorithms for the Domination Problems on Interval and Circular-Arc Graphs  

E-Print Network (OSTI)

Abstract. This paper first presents a unified approach to design efficient algorithms for the weighted domination problem and its three variants, i.e., the weighted independent, connected, and total domination problems, on interval graphs. Given an interval model with endpoints sorted, these algorithms run in time O(n) orO(n log log n) where n is the number of vertices. The results are then extended to solve the same problems on circular-arc graphs in O(n + m) time where m is the number of edges of the input graph.

Maw-shang Chang

1998-01-01T23:59:59.000Z

266

Low Cost Arc Fault Detection and Protection for PV Systems: January 30, 2012 - September 30, 2013  

SciTech Connect

Final report for Tigo Energy Incubator project. The specific objective of this 18-month research effort was to develop an off-the-shelf arc-fault detector. The starting point of the project was a prototype detector that was constructed using discrete components and laboratory equipment. An intermediate objective was to build a technically viable detector using programmable components in the detector circuitry. The final objective was to build a commercially viable detector by reducing the cost of the circuitry through the use of more sophisticated programmable components and higher levels of integration.

McCalmont, S.

2013-10-01T23:59:59.000Z

267

The Radiative Transfer Of CH{sub 4}-N{sub 2} Plasma Arc  

Science Conference Proceedings (OSTI)

Any physical modelling of a circuit-breaker arc therefore requires an understanding of the radiated energy which is taken into account in the form of a net coefficient. The evaluation of the net emission coefficient is performed by the knowledge of the chemical plasma composition and the resolution of the radiative transfer equation. In this paper, the total radiation which escapes from a CH{sub 4}-N{sub 2} plasma is calculated in the temperature range between 5000 and 30000K on the assumption of a local thermodynamic equilibrium and we have studied the nitrogen effect in the hydrocarbon plasmas.

Benallal, R. [Theoretical physics Laboratory, Physics Department of University Aboubekr Belkaied Tlemcen 13000 (Algeria); Liani, B. [Science Faculty, Hassiba Benbouali University, Chlef 02000 (Algeria)

2008-09-23T23:59:59.000Z

268

Integration of Predicted Atmospheric Contaminant Plumes into ArcView GIS  

Science Conference Proceedings (OSTI)

The Savannah River National Laboratory (SRNL) plays a key role in emergency response scenarios in which there may be a release of atmospheric chemical or radiological contamination at the DOE's Savannah River Site (SRS). Meteorologists at SRNL use a variety of tools to predict the path of the plume and levels of contamination along the path. These predictions are used to guide field teams that take sample measurements for verification. Integration of these predicted plumes as well as field measurements into existing Geographic Information System (GIS) interactive maps provides key additional information for decision makers during an emergency. In addition, having this information in GIS format facilitates sharing the information with other agencies that use GIS. In order to be useful during an emergency, an application for converting predictions or measurements into GIS format must be automated and simple to use. Thus, a key design goal in developing such applications is ease of use. Simple menu selections and intuitive forms with graphical user interfaces are used to accomplish this goal. Applications have been written to convert two different predictive code results into ArcView GIS. Meteorologists at SRNL use the Puff/Plume code, which is tied to real-time wind data, to predict the direction and spread of the atmospheric plume for early assessment. The calculated circular puffs are converted into an ArcView polygon shapefile with attributes for predicted time, dose, and radius of the puff. The meteorologists use the more sophisticated Lagrangian Particle Dispersion Model (LPDM) to predict particle dispersion and deposition. The calculational grid is brought into ArcView as a point shapefile and then interpolated to ARC GRID format using Spatial Analyst. This GRID can then be contoured into a line shapefile, which is easily shared with other agencies. The deposition grid is also automatically contoured for values that correspond to FDA Derived Intervention Levels for beef, produce, and dairy products. Decision makers at SRS routinely use these predicted plumes to direct field teams. In the case of a strong release, this information can be used to decide whether to evacuate a particular area. Having this information in GIS format may aid the decision maker because other infrastructure information can be overlaid with geographic reference.

Koffman, Larry D.

2005-10-10T23:59:59.000Z

269

Standard Practice for Measuring Plasma Arc Gas Enthalpy by Energy Balance  

E-Print Network (OSTI)

1.1 This practice covers the measurement of total gas enthalpy of an electric-arc-heated gas stream by means of an overall system energy balance. This is sometimes referred to as a bulk enthalpy and represents an average energy content of the test stream which may differ from local values in the test stream. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

American Society for Testing and Materials. Philadelphia

2008-01-01T23:59:59.000Z

270

Treatment studies of plutonium-bearing INEEL waste surrogates in a bench-scale arc furnace  

SciTech Connect

Since 1989, the Subsurface Disposal Area (SDA) at the Idaho National Environmental and Engineering Laboratory (INEEL) has been included on the National Priority List for remediation. Arc- and plasma-heated furnaces are being considered for converting the radioactive mixed waste buried in the SDA to a stabilized-vitreous form. Nonradioactive, surrogate SDA wastes have been melted during tests in these types of furnaces, but data are needed on the behavior of transuranic (TRU) constituents, primarily plutonium, during thermal treatment. To begin collecting this data, plutonium-spiked SDA surrogates were processed in a bench-scale arc furnace to quantify the fate of the plutonium and other hazardous and nonhazardous metals. Test conditions included elevating the organic, lead, chloride, and sodium contents of the surrogates. Blends having higher organic contents caused furnace power levels to fluctuate. An organic content corresponding to 50% INEEL soil in a soil-waste blend was the highest achievable before power fluctuations made operating conditions unacceptable. The glass, metal, and off-gas solids produced from each surrogate blend tested were analyzed for elemental (including plutonium) content and the partitioning of each element to the corresponding phase was calculated.

Freeman, C.J.

1997-05-01T23:59:59.000Z

271

CalHypso: An ArcGIS extension to calculate hypsometric curves and their statistical moments. Applications to drainage basin analysis in SE Spain  

Science Conference Proceedings (OSTI)

We present the GIS extension CalHypso to automatically extract multiple hypsometric curves from digital elevation models (DEM). This extension is programmed in Visual Basic 6 and uses the ArcObjects architecture of ArcGIS. It employs a new and easy methodology ... Keywords: Active tectonics, Betic Cordillera, GIS extension, Hypsometric curve, Sierra Nevada

J. V. Pérez-Peña; J. M. Azañón; A. Azor

2009-06-01T23:59:59.000Z

272

Atomic-scale properties of semiconductor heterostructures probed by scanning tunneling microscopy  

SciTech Connect

The engineering of advanced semiconductor heterostructure materials and devices requires a detailed understanding of, and control over, the structure and properties of semiconductor materials and devices at the atomic to nanometer scale. Cross-sectional scanning tunneling microscopy has emerged as a unique and powerful method to characterize structural morphology and electronic properties in semiconductor epitaxial layers and device structures at these length scales. The basic experimental techniques in cross-sectional scanning tunneling microscopy are described, and some representative applications to semiconductor heterostructure characterization drawn from recent investigations in the authors laboratory are discussed. Specifically, they describe some recent studies of InP/InAsP and InAsP/InAsSb heterostructures in which nanoscale compositional clustering has been observed and analyzed.

Yu, E.T.; Zuo, S.L.; Bi, W.G.; Tu, C.W. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Electrical and Computer Engineering; Biefeld, R.M.; Allerman, A.A. [Sandia National Labs., Albuquerque, NM (United States)

1998-05-01T23:59:59.000Z

273

A general kinetic model: Kinetics and atomic-scale mechanisms of feldspar dissolution.  

E-Print Network (OSTI)

??This thesis presents a general kinetic model and its application to feldspar dissolution. In the framework of Monte Carlo methods, the model simulates the stochastic… (more)

Zhang, Li

2008-01-01T23:59:59.000Z

274

Controllable Atomic Scale Patterning of Freestanding Monolayer Graphene at Elevated Temperature  

E-Print Network (OSTI)

cross-sections for graphene knock-on damage and STEM imaging. Two threshold voltages 140 kV (red line are multiple times. Figure S3. High-resolution STEM imaging of graphene at 700 °C using 300 kV electrons (outlined by red lines). (b) at room temperature, scanning electron beam on graphene induced contamination

Dunin-Borkowski, Rafal E.

275

Atomic-Scale Mechanisms of Oxygen Electrode Delamination in Solid Oxide Electrolyzer Cells  

DOE Green Energy (OSTI)

Materials used for different components (electrodes, electrolyte, steel interconnects, etc.) of solid oxide electrolyzer cell (SOEC) devices for hydrogen production have to function in aggressive, corrosive environments and in the presence of electric fields. This results in a number of degradation processes at interfaces between components. In this study, we used a combination of first-principles, density-functional-theory (DFT) calculations and thermodynamic modeling to elucidate the main processes that contribute into the oxygen delamination in typical SOEC device consisting of yttria-stabilized zirconia (YSZ) electrolyte and Sr-doped LaMnO3 (LSM) oxygen electrode. We found that high temperature inter-diffusion of different atoms across the LSM/YSZ interface significantly affects structural stability of the materials and their interface. In particular, we found that La and Sr substitutional defects positioned in ZrO2 oxide and near LSM/YSZ interface significantly change oxygen transport which may develop pressure buildup in the interfacial region and eventually develop delamination process. Simple models for estimating these effects are proposed, and different possibilities for inhibiting and/or mitigating undesirable delamination processes are discussed.

Sergey N. Rashkeev; Michael V. Glazoff

2012-01-01T23:59:59.000Z

276

Phase-field crystal modeling and atomic-scale characterization of ...  

Science Conference Proceedings (OSTI)

The simulation results are compared with the findings of atomic-level electron microscopy ... Evolution of precipitate nuclei during age-hardening · Evolution of  ...

277

Atomic scale studies of interface formation between oxides and III-V semiconductor surfaces  

E-Print Network (OSTI)

volatile [151], but indium oxides are not [156]; therefore,with them having an indium oxide composition. Bulk In 2 O 3temperatures and the indium oxides remain in the form of

Clemens, Jonathon Boyd

2010-01-01T23:59:59.000Z

278

NIST Researchers Holding Steady in an Atomic-Scale Tug-of ...  

Science Conference Proceedings (OSTI)

... The chart records quantum jumps in conductivity as a gold contact is ... Simultaneously, a tiny electric current flowing between the surface and probe ...

2012-10-18T23:59:59.000Z

279

and Rutile TiO2(110) Surfaces at an Atomic Scale  

Science Conference Proceedings (OSTI)

N11: Microbilogically Influenced Corrosion of Pipeline Steels used in Oil & Gas ... Numerical Modelling for Characterising the Flammability of Natural Fibre ...

280

Atomic scale control of catalytic process in oxidation of Pb thin films  

SciTech Connect

Using scanning tunneling microscopy (STM), we demonstrate that oxidation on Pb films is greatly enhanced by atomic Cs catalysts. With only a minute concentration of isolated Cs substitutional atoms in the surface layer (0.004 ML coverage), surface oxidation rates are greatly enhanced. First-principles density functional theory (DFT) calculations reveal that a substitutional Cs atom strongly increases O2 binding on the surface. Then, with additional oxygen exposure this substitutional Cs-initiated oxidation process results in growth of PbO layers in an auto-catalytic manner. Furthermore, we investigate the role of temperature in the oxidation of the Pb films with and without Cs, and we explore the overall morphology of the resultant oxide layers.

Kim, Jisun [University of Texas, Austin; Khajetoorians, Alexander Ako [University of Texas, Austin; Zhu, Wenguang [ORNL; Zhang, Zhenyu [ICQD, University of S& T, Hefei, China; Shih, Chih-Kang [University of Texas, Austin

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

The problem of an obducting lithospheric plate in the Aleutian arc system. A finite element analysis in the frictionless case  

Science Conference Proceedings (OSTI)

A model of the Aleutian arc system is studied from the point of view of a plate tectonic concept based on the global geodynamic model. In our model problem we limit ourselves to a model in which the lithospheric plate is obducting with time onto the ...

J. Nedoma; J. Haslinger; I. Hlaváek

1989-01-01T23:59:59.000Z

282

Model-based analysis of an arc protection and an emergency cooling system  

E-Print Network (OSTI)

Instrumentation and control (I&C) systems play a crucial role in the operation of nuclear power plants and other safety critical processes. An important change that will be going on in the near future is the replacement of the old analogue I&C systems by new digitalised ones. The programmable digital logic controllers enable more complicated control tasks than the old analogue systems and thus the verification of the control logic designs against safety requirements has become more important. In order to diminish the subjective component of the evaluation, there is a need to develop new formal verification methods. This report summarizes the work done in the MODSAFE 2007 project on two case studies where model checking techniques have been used to study an arc protection system and an emergency cooling system. Model checking tools offer typically a finite state machine based

Janne Valkonen; Ville Pettersson; Kim Björkman; Jan-erik Holmberg; Matti Koskimies; Keijo Heljanko; Ilkka Niemelä

2008-01-01T23:59:59.000Z

283

Railguns and plasma accelerators: arc armatures, pulse power sources and US patents  

SciTech Connect

Railguns and plasma accelerators have the potential for use in many basic and applied research projects, such as in creating high-pressures for equation-of-state studies and in impact fusion. A brief review of railguns and plasma accelerators with references is presented. Railgun performance is critically dependent on armature operation. Plasma arc railgun armatures are addressed. Pulsed power supplies for multi-stage railguns are considered. This includes brief comments on the compensated pulsed alternator, or compulsator, rotating machinery, and distributed energy sources for railguns. References are given at the end of each section. Appendix A contains a brief review of the US Patents on multi-staging techniques for electromagnetic accelerators, plasma propulsion devices, and electric guns.

Friedrich, O.M. Jr.

1980-11-01T23:59:59.000Z

284

Influence of nosetip shape on boundary layer transition in arc heated jets  

SciTech Connect

The effect of model shape on the graphite recession rate and boundary layer transition was studied in an arc jet over the pressure and enthalpy ranges of 0.99 to 20.7 MPa (9.8 to 204 atm) and 3416 to 15640J/g (1470 to 6730 Btu;lb), respectively. Hemispheric, flat-faced and conic cylindrical models were used. It was found that resistance to transition occurs in the order of flat-faced > conic > hemispheric shape. Evidence of this behavior is provided in terms of the relative ablation rates associated with each shape and the times-to-transition. The differences in resistance to transition are appreciable and suggest that reentry vehicles would benefit with respect to nosetip shape change by changing from the conventional hemispheric shape to a conic or, preferably, a flat-faced configuration.

Auerbach, I.

1978-01-01T23:59:59.000Z

285

All Other Edi~ims Arc Obolete United States Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

9-0s) 9-0s) All Other Edi~ims Arc Obolete United States Department of Energy E n e r g Finance and account in^ Sen'ice Center Travel Authorization and Program Manager Signature Card Name: Date: Position Title: Routing Symbol: BuiIding: Phone: Reporting EntityFund Code: Signature: Typcs of Documents Authorized (please check box) Approved Funding Program Change Request Procurement Authorization (PRs, direct chargebacks. etc.) Claim for Reimbursement for Espenditwre on Official Business (Local Travel) Travel Authorizations and Nodi fications Travel Vouchers Training Authorizations Training Invoice Payments Invoice Payment Approval Travel Authorizations and Modifications (actual expenses) Other (speci fyS - I certifL to the signature and authority of the above individual for the document noted.

286

TEAM HEV ARC HITECTURE ENGIN E FU EL TRANS MISSION EN ERGY STOR  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

TEAM TEAM HEV ARC HITECTURE ENGIN E FU EL TRANS MISSION EN ERGY STOR AGE MO TOR Michigan Technological University Through-the-road Parallel 2.0-L 4 Cylinder Spark Ignition Reformulated Gasoline 4-speed Automatic COBASYS, Nickel Metal Hydride - 288V 50 kW Solectria AC Induction Transaxle Mississippi State University Through-the-road Parallel 1.9-L GM Direct Injection Turbo Diesel Bio Diesel (B20) GM F40 6-speed Manual Johnson Controls, Nickel Metal Hydride - 330V 45 kW Ballard Integrated Power Transaxle The Ohio State University Through-the-road Parallel 1.9-L GM Direct Injection Turbo Diesel Bio Diesel (B20) Aisin-Warner AF40 6-speed Automatic Transaxle Panasonic, Nickel Metal Hydride - 300V 67 kW Ballard AC Induction Transaxle /10.6 kW Kollmorgen Brushless DC Generator Pennsylvania State

287

Method for processing aluminum spent potliner in a graphite electrode arc furnace  

DOE Patents (OSTI)

A method of processing spent aluminum pot liner containing carbon, cyanide compositions, fluorides and inorganic oxides. The spend aluminum pot liner is crushed, iron oxide is added to form an agglomerated material. The agglomerated material is melted in an electric arc furnace having the electrodes submerged in the molten material to provide a reducing environment during the furnace operation. In the reducing environment, pot liner is oxidized while the iron oxides are reduced to produce iron and a slag substantially free of cyanide compositions and fluorides. An off-gas including carbon oxides and fluorine is treated in an air pollution control system with an afterburner and a scrubber to produce NaF, water and a gas vented to the atmosphere free of cyanide compositions, fluorine, and CO.

O' Connor, William K.; Turner, Paul C.; Addison, G.W. (AJT Enterprises, Inc.)

2002-12-24T23:59:59.000Z

288

Method for processing aluminum spent potliner in a graphite electrode ARC furnace  

SciTech Connect

A method of processing spent aluminum pot liner containing carbon, cyanide compositions, fluorides and inorganic oxides. The spent aluminum pot liner is crushed iron oxide is added to form an agglomerated material. The agglomerated material is melted in an electric arc furnace having the electrodes submerged in the molten material to provide a reducing environment during the furnace operation. In the reducing environment, pot liner is oxidized while the iron oxides are reduced to produce iron and a slag substantially free of cyanide compositions and fluorides. An off-gas including carbon oxides and fluorine is treated in an air pollution control system with an afterburner and a scrubber to produce NaF, water and a gas vented to the atmosphere free of cyanide compositions, fluorine and CO.

O' Connor, William K. (Lebanon, OR); Turner, Paul C. (Independence, OR); Addison, Gerald W. (St. Stephen, SC)

2002-12-24T23:59:59.000Z

289

In-Flight Oxidation of Aluminum in the Twin-Wire Electric Arc Process  

Science Conference Proceedings (OSTI)

This paper examines the in-flight oxidation of aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. Aerodynamic shear at the droplet surface increases the amount of in-flight oxidation by promoting entrainment of the surface oxides within the molten droplet and continually exposing fresh fluid available for oxidation. Mathematical predictions herein confirm experimental measurements that reveal an elevated, nearly constant surface temperature (~2273 K) of the droplets during flight. The calculated oxide volume fraction of a “typical” droplet with internal circulation compares favorably to the experimentally determined oxide content (3.3 to 12.7%) for a typical TWEA-sprayed aluminum coating sprayed onto a room temperature substrate. It is concluded that internal circulation within the molten aluminum droplet is a significant source of oxidation. This effect produces an oxide content nearly two orders of magnitude larger than that of a droplet without continual oxidation.

Donna Post Guillen; Brian G. Williams

2006-03-01T23:59:59.000Z

290

Evaluation of the graphite electrode arc melter for processing heterogeneous waste  

SciTech Connect

The U.S. Bureau of Mines (USBM) conducted a series of 4 demonstration melting tests in a 3-phase AC graphite electrode arc furnace at its Albany Research Center (ALRC) thermal treatment facility in Albany, Oregon (now part of the U.S. Department of Energy, DOE). The scope of these tests provides a unique opportunity to evaluate a single melting technology regarding its applicability to the treatment of several different heterogeneous mixed wastes. The current system can continuously process combustible-bearing wastes at feedrates to 682 kg/h (1,500 lb/h), continuously tap slag or glass, and intermittently tap metal products, and includes a close-coupled thermal oxidizer and air pollution control system (APCS). The 4 demonstration melting tests were conducted in cooperation with the American Society of Mechanical Engineers (ASME), the Idaho National Engineering Laboratory (INEL), and the Westinghouse Hanford Company (WHC).

O' Connor, William K.; Turner, Paul C.; Soelberg, N.R. (Idaho National Engineering Laboratory); Anderson, G.L. (Idaho National Engineering Laboratory)

1996-01-01T23:59:59.000Z

291

Mechanical Characteristics of Submerged Arc Weldment in API Gas Pipeline Steel of Grade X65  

Science Conference Proceedings (OSTI)

The mechanical properties of submerged arc weldment (SAW) in gas transportation pipeline steel of grade API X65 (65 ksi yield strength) were investigated. This steel is produced by thermo mechanical control rolled (TMC), and is largely used in Iran gas piping systems and networks. The results from laboratory study on three different regions; i.e. base metal (BM), fusion zone (FZ) and heat affected zone (HAZ) were used to compare weldment mechanical characteristics with those specified by API 5L (revision 2004) standard code. Different laboratory experiments were conducted on test specimens taken from 48 inch outside diameter and 14.3 mm wall thickness gas pipeline. The test results showed a gradient of microstructure and Vickers hardness data from the centerline of FZ towards the unaffected MB. Similarly, lower Charpy absorbed energy (compared to BM) was observed in the FZ impact specimens. Despite this, the API specifications were fulfilled in three tested zones, ensuring pipeline structural integrity under working conditions.

Hashemi, S. H. [Department of Mechanical Engineering, University of Birjand, POBOX 97175-376, Birjand (Iran, Islamic Republic of); Mohammadyani, D. [Materials and Energy Research Center (MERC) POBOX 14155-4777, Tehran (Iran, Islamic Republic of)

2011-01-17T23:59:59.000Z

292

THERMAL ANNEALING OF ZNO FILMS USING HIGH-DENSITY PLASMA ARC LAMPS  

Science Conference Proceedings (OSTI)

Nanostructured materials are rarely synthesized with appropriate phase and/or morphology. In this study, critical additional of as-synthesized nanostructured materials, such as annealing and/or activation of dopants, are addressed using infrared plasma arc lamps (PAL) over areas as large as 1,000 cm2. The broad spectral range of the PAL and the spectral variation of light absorption in nanostructured materials make the selection of processing parameters extremely difficult, posing a major technological barrier. In this study, the measurement of the surface temperature using various techniques for ZnO films on crystalline silicon wafers is discussed. An energy transport model for the simulation of rapid thermal processing using PAL is presented. The experimental and computational results show that the surface temperature cannot be measured directly and that computer simulation results are an effective tool for obtaining accurate data on processing temperatures.

Sabau, Adrian S [ORNL; Dinwiddie, Ralph Barton [ORNL; Xu, Jun [ORNL; Angelini, Joseph Attilio [ORNL; Harper, David C [ORNL

2011-01-01T23:59:59.000Z

293

Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder Metallurgy Produced Titanium Alloys  

Science Conference Proceedings (OSTI)

ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

Muth, Thomas R [ORNL; Yamamoto, Yukinori [ORNL; Frederick, David Alan [ORNL; Contescu, Cristian I [ORNL; Chen, Wei [ORNL; Lim, Yong Chae [ORNL; Peter, William H [ORNL; Feng, Zhili [ORNL

2013-01-01T23:59:59.000Z

294

Final Design And Manufacturing of the PEP II High Energy Ring Arc Bellows Module  

SciTech Connect

A novel RF shield bellows module developed at SLAC has been successfully manufactured and installed in the PEP-II High Energy Ring (HER). Tests indicate that the module meets its performance and operational requirements. The primary function of the bellows module is to allow for thermal expansion of the chambers and for lateral, longitudinal and angular offsets due to tolerances and alignment, while providing RF continuity between adjoining chambers. An update on the Arc bellows module for the PEP-II High Energy Ring is presented. Final design, manufacturing issues, material and coating selection, and tribological and RF testing are discussed. Performance and operational requirements are also reviewed. The RF shield design has been proven during assembly to allow for large manufacturing tolerances without reducing the mechanical spring force below required values. In addition, the RF shield maintains electrical contact even with large misalignments across the module.

Kurita, Nadine R.; Kulikov, Artem; /SLAC; Corlett, John; /LBL, Berkeley

2011-09-01T23:59:59.000Z

295

Contamination due to memory effects in filtered vacuum arc plasma deposition systems  

SciTech Connect

Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the SRIM (Stopping and Range of Ions in Matter) code. We find film contamination of order 10-4 - 10-3, and the memory of the prior history of the deposition hardware can be relatively long-lasting.

Martins, D.R.; Salvadori, M.C.; Verdonck, P.; Brown, I.G.

2002-08-13T23:59:59.000Z

296

Kilovoltage Intrafraction Monitoring for Prostate Intensity Modulated Arc Therapy: First Clinical Results  

SciTech Connect

Purpose: Most linear accelerators purchased today are equipped with a gantry-mounted kilovoltage X-ray imager which is typically used for patient imaging prior to therapy. A novel application of the X-ray system is kilovoltage intrafraction monitoring (KIM), in which the 3-dimensional (3D) tumor position is determined during treatment. In this paper, we report on the first use of KIM in a prospective clinical study of prostate cancer patients undergoing intensity modulated arc therapy (IMAT). Methods and Materials: Ten prostate cancer patients with implanted fiducial markers undergoing conventionally fractionated IMAT (RapidArc) were enrolled in an ethics-approved study of KIM. KIM involves acquiring kV images as the gantry rotates around the patient during treatment. Post-treatment, markers in these images were segmented to obtain 2D positions. From the 2D positions, a maximum likelihood estimation of a probability density function was used to obtain 3D prostate trajectories. The trajectories were analyzed to determine the motion type and the percentage of time the prostate was displaced {>=}3, 5, 7, and 10 mm. Independent verification of KIM positional accuracy was performed using kV/MV triangulation. Results: KIM was performed for 268 fractions. Various prostate trajectories were observed (ie, continuous target drift, transient excursion, stable target position, persistent excursion, high-frequency excursions, and erratic behavior). For all patients, 3D displacements of {>=}3, 5, 7, and 10 mm were observed 5.6%, 2.2%, 0.7% and 0.4% of the time, respectively. The average systematic accuracy of KIM was measured at 0.46 mm. Conclusions: KIM for prostate IMAT was successfully implemented clinically for the first time. Key advantages of this method are (1) submillimeter accuracy, (2) widespread applicability, and (3) a low barrier to clinical implementation. A disadvantage is that KIM delivers additional imaging dose to the patient.

Ng, Jin Aun [Radiation Physics Laboratory, Sydney Medical School and Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia) [Radiation Physics Laboratory, Sydney Medical School and Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Booth, Jeremy T. [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia) [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Poulsen, Per R.; Fledelius, Walther; Worm, Esben Schjodt [Department of Oncology, Aarhus University Hospital, Denmark, and Institute of Clinical Medicine, Aarhus University (Denmark)] [Department of Oncology, Aarhus University Hospital, Denmark, and Institute of Clinical Medicine, Aarhus University (Denmark); Eade, Thomas; Hegi, Fiona; Kneebone, Andrew [Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia)] [Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Kuncic, Zdenka [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia)] [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Keall, Paul J., E-mail: paul.keall@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School and Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia)

2012-12-01T23:59:59.000Z

297

High energy arcing fault fires in switchgear equipment : a literature review.  

SciTech Connect

In power generating plants, switchgear provide a means to isolate and de-energize specific electrical components and buses in order to clear downstream faults, perform routine maintenance, and replace necessary electrical equipment. These protective devices may be categorized by the insulating medium, such as air or oil, and are typically specified by voltage classes, i.e. low, medium, and high voltage. Given their high energy content, catastrophic failure of switchgear by means of a high energy arcing fault (HEAF) may occur. An incident such as this may lead to an explosion and fire within the switchgear, directly impact adjacent components, and possibly render dependent electrical equipment inoperable. Historically, HEAF events have been poorly documented and discussed in little detail. Recent incidents involving switchgear components at nuclear power plants, however, were scrupulously investigated. The phenomena itself is only understood on a very elementary level from preliminary experiments and theories; though many have argued that these early experiments were inaccurate due to primitive instrumentation or poorly justified methodologies and thus require re-evaluation. Within the past two decades, however, there has been a resurgence of research that analyzes previous work and modern technology. Developing a greater understanding of the HEAF phenomena, in particular the affects on switchgear equipment and other associated switching components, would allow power generating industries to minimize and possibly prevent future occurrences, thereby reducing costs associated with repair and downtime. This report presents the findings of a literature review focused on arc fault studies for electrical switching equipment. The specific objective of this review was to assess the availability of the types of information needed to support development of improved treatment methods in fire Probabilistic Risk Assessment (PRA) for nuclear power plant applications.

Nowlen, Steven Patrick; Brown, Jason W.; Wyant, Francis John

2008-10-01T23:59:59.000Z

298

Fluid flow, element migration, and petrotectonic evolution of the Early Mesozoic central Klamath Island arc, northwesternmost California. Progress report  

SciTech Connect

Investigations in the central Klamath Mountains (KM) have documented the presence of a polymetamorphosed suite of highly magnesian basaltic rocks, the Yellow Dog greenstones, in the Sawyers Bar (SB) terrane of the western Triassic and Paleozoic belt. The assemblage was laid down, altered and metasomatized during the hypothesized collapse of a Phillipine Sea-type back-arc basin which brought the westerly SB oceanic arc terrane into juxtaposition with the inboard, pre-existing Stuart Fork subduction complex, and more easterly KM terranes in an immature island arc setting. Supporting research has concentrated on elucidating the areal extent and structural/stratigraphic relations of these mafic/ultramafic Yellow Dog metavolcanic units, and has documented the insignificant degree of crustal contamination of the melts by associated terrigenous metasediments. The thermal structure and its evolution in the central KM evidently reflects surfaceward advective transport of magmatic energy derived from the partly fused downgoing oceanic slab, as well as hydrothermal fluid circulation. Clarification of the thermal evolution of this crust-constructional event in the immature basaltic island arc are the goals of the research now underway, emptying both field and geochemical methods. Continuing work is documenting the flow and P-T history of aqueous fluids through the evolving KM arc, utilizing electron microprobe and oxygen isotopic data. The authors have nearly finished a regional reconnaissance map showing the distribution of the lavas throughout the California part of the KM. Application of the terrane concept to the central KM has also been reevaluated in the light of regional petrotectonic relationships. Investigations of the regional and contact metamorphism/metasomatism of the SB metasedimentary pile are in progress.

Ernst, W.G.

1992-12-11T23:59:59.000Z

299

Excursions in Chemical Dynamics  

E-Print Network (OSTI)

2009). [118] F. A. Cotton, Chemical Applications of GroupExcursions in Chemical Dynamics by Shervin Fatehi AFall 2010 Excursions in Chemical Dynamics Copyright 2010 by

Fatehi, Shervin

2010-01-01T23:59:59.000Z

300

Detonation shock dynamics calibration for pBX 9502 with temperature, density, and material lot variations  

Science Conference Proceedings (OSTI)

We present a methodology for scaling the detonation shock dynamics D{sub n}[{kappa}] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T{sub 0}, nominal density {rho}{sub 0}, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, {delta}. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on {delta}. This results in a D{sub n}[{kappa}] function that depends on T{sub 0}, {rho}{sub 0}, and {delta}. After examining the separate effects of each parameter on D{sub n}[{kappa}], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

Hill, Larry G [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Detection and correction for EPID and gantry sag during arc delivery using cine EPID imaging  

Science Conference Proceedings (OSTI)

Purpose: Electronic portal imaging devices (EPIDs) have been studied and used for pretreatment and in-vivo dosimetry applications for many years. The application of EPIDs for dosimetry in arc treatments requires accurate characterization of the mechanical sag of the EPID and gantry during rotation. Several studies have investigated the effects of gravity on the sag of these systems but each have limitations. In this study, an easy experiment setup and accurate algorithm have been introduced to characterize and correct for the effect of EPID and gantry sag during arc delivery. Methods: Three metallic ball bearings were used as markers in the beam: two of them fixed to the gantry head and the third positioned at the isocenter. EPID images were acquired during a 360 deg. gantry rotation in cine imaging mode. The markers were tracked in EPID images and a robust in-house developed MATLAB code was used to analyse the images and find the EPID sag in three directions as well as the EPID + gantry sag by comparison to the reference gantry zero image. The algorithm results were then tested against independent methods. The method was applied to compare the effect in clockwise and counter clockwise gantry rotations and different source-to-detector distances (SDDs). The results were monitored for one linear accelerator over a course of 15 months and six other linear-accelerators from two treatment centers were also investigated using this method. The generalized shift patterns were derived from the data and used in an image registration algorithm to correct for the effect of the mechanical sag in the system. The Gamma evaluation (3%, 3 mm) technique was used to investigate the improvement in alignment of cine EPID images of a fixed field, by comparing both individual images and the sum of images in a series with the reference gantry zero image. Results: The mechanical sag during gantry rotation was dependent on the gantry angle and was larger in the in-plane direction, although the patterns were not identical for various linear-accelerators. The reproducibility of measurements was within 0.2 mm over a period of 15 months. The direction of gantry rotation and SDD did not affect the results by more than 0.3 mm. Results of independent tests agreed with the algorithm within the accuracy of the measurement tools. When comparing summed images, the percentage of points with Gamma index <1 increased from 85.4% to 94.1% after correcting for the EPID sag, and to 99.3% after correction for gantry + EPID sag. Conclusions: The measurement method and algorithms introduced in this study use cine-images, are highly accurate, simple, fast, and reproducible. It tests all gantry angles and provides a suitable automatic analysis and correction tool to improve EPID dosimetry and perform comprehensive linac QA for arc treatments.

Rowshanfarzad, Pejman; Sabet, Mahsheed; O'Connor, Daryl J.; McCowan, Peter M.; McCurdy, Boyd M. C.; Greer, Peter B. [School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW 2308 (Australia); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada) and Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Division of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physics and Astronomy, University of Manitoba,Winnipeg, Manitoba R3T 2N2 (Canada) and Department of Radiology, University of Manitoba, Winnipeg, Manitoba R3A 1R9 (Canada); Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, NSW 2310 (Australia) and School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW 2308 (Australia)

2012-02-15T23:59:59.000Z

302

Dynamic Analysis of Wind Turbine Planetary Gears Using an Extended Harmonic Balance Approach: Preprint  

DOE Green Energy (OSTI)

The dynamics of wind turbine planetary gears with gravity effects are investigated using an extended harmonic balance method that extends established harmonic balance formulations to include simultaneous internal and external excitations. The extended harmonic balance method with arc-length continuation and Floquet theory is applied to a lumped-parameter planetary gear model including gravity, fluctuating mesh stiffness, bearing clearance, and nonlinear tooth contact to obtain the planetary gear dynamic response. The calculated responses compare well with time domain integrated mathematical models and experimental results. Gravity is a fundamental vibration source in wind turbine planetary gears and plays an important role in system dynamics, causing hardening effects induced by tooth wedging and bearing-raceway contacts. Bearing clearance significantly reduces the lowest resonant frequencies of translational modes. Gravity and bearing clearance together lowers the speed at which tooth wedging occurs lower than the resonant frequency.

Guo, Y.; Keller, J.; Parker, R. G.

2012-06-01T23:59:59.000Z

303

Novel Direct Steelmaking by Combining Microwave, Electric Arc, and Exothermal Heating Technologies  

SciTech Connect

Steel is a basic material broadly used by perhaps every industry and individual. It is critical to our nation's economy and national security. Unfortunately, the American steel industry is losing competitiveness in the world steel production field. There is an urgent need to develop the next generation of steelmaking technology for the American steel industry. Direct steelmaking through the combination of microwave, electric arc, and exothermal heating is a revolutionary change from current steelmaking technology. This technology can produce molten steel directly from a shippable agglomerate, consisting of iron oxide fines, powdered coal, and ground limestone. This technology is projected to eliminate many current intermediate steelmaking steps including coking, pellet sintering, blast furnace (BF) ironmaking, and basic oxygen furnace (BOF) steelmaking. This technology has the potential to (a) save up to 45% of the energy consumed by conventional steelmaking; (b) dramatically reduce the emission of CO{sub 2}, SO{sub 2}, NO{sub x}, VOCs, fine particulates, and air toxics; (c) substantially reduce waste and emission control costs; (d) greatly lower capital cost; and (e) considerably reduce steel production costs. This technology is based on the unique capability of microwaves to rapidly heat steelmaking raw materials to elevated temperature, then rapidly reduce iron oxides to metal by volumetric heating. Microwave heating, augmented with electric arc and exothermal reactions, is capable of producing molten steel. This technology has the components necessary to establish the ''future'' domestic steel industry as a technology leader with a strong economically competitive position in world markets. The project goals were to assess the utilization of a new steelmaking technology for its potential to achieve better overall energy efficiency, minimize pollutants and wastes, lower capital and operating costs, and increase the competitiveness of the U.S. steel industry. The objectives associated with this goal were to (a) generate a solid base of technical, marketing, economic, and policy data, (b) develop energy, environmental, and economic targets, (c) more definitively assess opportunities and barriers, (d) accumulate knowledge and experience for defining direction for the next phase of development, and (e) promote learning and training of students.

Dr. Xiaodi Huang; Dr. J. Y. Hwang

2005-03-28T23:59:59.000Z

304

Dosimetric aspects of inverse-planned modulated-arc total-body irradiation  

Science Conference Proceedings (OSTI)

Purpose: To develop optimal beam parameters and to verify the dosimetric aspects of the recently developed modulated-arc total-body irradiation (MATBI) technique, which delivers an inverse-planned dose to the entire body using gantry rotation. Methods: The patient is positioned prone and supine underneath the gantry at about 2 m source-to-surface distance (SSD). Then, up to 28 beams irradiate the patient from different gantry angles. Based on full-body computed-tomography (CT) images of the patient, the weight of each beam is optimized, using inverse planning, to create a uniform body dose. This study investigates how to best simulate patients and the ideal beam setup parameters, such as field size, number of beams, and beam geometry, for treatment time and dose homogeneity. In addition, three anthropomorphic water phantoms were constructed and utilized to verify the accuracy of dose delivery, with both diode array and ion chamber measurements. Furthermore, to improve the accuracy of the new technique, a beam model is created specifically for the extended-SSD positioning for MATBI. Results: Low dose CT scans can be utilized for dose calculations without affecting the accuracy. The largest field size of 40 Multiplication-Sign 40 cm{sup 2} was found to deliver the most uniform dose in the least amount of time. Moreover, a higher number of beams improves dose homogeneity. The average dose discrepancy between ion chamber measurements and extended-SSD beam model calculations was 1.2%, with the largest discrepancy being 3.2%. This average dose discrepancy was 1.4% with the standard beam model for delivery at isocenter. Conclusions: The optimum beam setup parameters, regarding dose uniformity and treatment duration, are laid out for modulated-arc TBI. In addition, the presented dose measurements show that these treatments can be delivered accurately. These measurements also indicated that a new beam model did not significantly improve the accuracy of dose calculations. The optimum beam setup parameters along with the measurements performed to ensure accurate dose delivery serve as a useful guide for the clinical implementation of MATBI.

Held, Mareike; Kirby, Neil; Morin, Olivier; Pouliot, Jean [Department of Radiation Oncology, University of California San Francisco, California 94143-1708 (United States)

2012-08-15T23:59:59.000Z

305

Validation of the ATSR Reprocessing for Climate (ARC) Dataset Using Data from Drifting Buoys and a Three-Way Error Analysis  

Science Conference Proceedings (OSTI)

The Along-Track Scanning Radiometer (ATSR) Reprocessing for Climate (ARC) project aims to create an independent climate data record of sea surface temperatures (SSTs) covering recent decades that can be used for climate change analysis. Here, the ...

Katie Lean; Roger W. Saunders

2013-07-01T23:59:59.000Z

306

Nitrogen Control in Electric Arc Furnace Steelmaking by DRI (TRP 0009)  

SciTech Connect

Nitrogen is difficult to remove in electric arc furnace (EAF) steelmaking, requiring the use of more energy in the oxygen steelmaking route to produce low-nitrogen steel. The objective of this work was to determine if the injection of directly reduced iron (DRI) fines into EAFs could reduce the nitrogen content by creating fine carbon monoxide bubbles that rinse nitrogen from the steel. The proposed work included physical and chemical characterization of DRI fines, pilot-scale injection into steel, and mathematical modeling to aid in scale-up of the process. Unfortunately, the pilot-scale injections were unsuccessful, but some full-scale data was obtained. Therefore, the original objectives were met, and presented in the form of recommendations to EAF steelmakers regarding: (1) The best composition and size of DRI fines to use; (2) The amount of DRI fines required to achieve a specific reduction in nitrogen content in the steel; and (3) The injection conditions. This information may be used by steelmakers in techno-economic assessments of the cost of reducing nitrogen with this technology.

Dr. Gordon A. Irons

2004-03-31T23:59:59.000Z

307

Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: Circuitry and mechanical design  

Science Conference Proceedings (OSTI)

A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 {mu}s. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

Kia, Kaveh Kazemi [Department of Electrical and Computer Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of); Bonabi, Fahimeh [Department of Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of)

2012-12-15T23:59:59.000Z

308

Spectrographic temperature measurement of a high power breakdown arc in a high pressure gas switch  

Science Conference Proceedings (OSTI)

A procedure for obtaining an approximate temperature value of conducting plasma generated during self-break closure of a RIMFIRE gas switch is described. The plasma is in the form of a breakdown arc which conducts approximately 12 kJ of energy in 1 {mu}s. A spectrographic analysis of the trigger-section of the 6-MV RIMFIRE laser triggered gas switch used in Sandia National Laboratory's ''Z-Machine'' has been made. It is assumed that the breakdown plasma has sufficiently approached local thermodynamic equilibrium allowing a black-body temperature model to be applied. This model allows the plasma temperature and radiated power to be approximated. The gas dielectric used in these tests was pressurized SF{sub 6}. The electrode gap is set at 4.59 cm for each test. The electrode material is stainless steel and insulator material is poly(methyl methacrylate). A spectrum range from 220 to 550 nanometers has been observed and calibrated using two spectral irradiance lamps and three spectrograph gratings. The approximate plasma temperature is reported.

Yeckel, Christopher; Curry, Randy [Department of Computer and Electrical Engineering, Center for Physical and Power Electronics, University of Missouri--Columbia, Columbia, Missouri 65211 (United States)

2011-09-15T23:59:59.000Z

309

Capital requirements for the transportation of energy materials: 1979 ARC estimates. Draft final report  

SciTech Connect

This report contains TERA's estimates of capital requirements to transport natural gas, crude oil, petroleum products, and coal in the United States by 1990. The low, medium, and high world-oil-price scenarios from the EIA's Mid-range Energy Forecasting System (MEFS), as used in the 1979 Annual Report to Congress (ARC), were provided as a basis for the analysis and represent three alternative futures. TERA's approach varies by energy commodity to make best use of the information and analytical tools available. Summaries of transportation investment requirements through 1990 are given. Total investment requirements for three modes (pipelines, rails, waterways and the three energy commodities can accumulate to a $49.9 to $50.9 billion range depending on the scenario. The scenarios are distinguished primarily by the world price of oil which, given deregulation of domestic oil prices, affects US oil prices even more profoundly than in the past. The high price of oil, following the evidence of the last year, is projected to hold demand for oil below the recent past.

Not Available

1980-08-13T23:59:59.000Z

310

LARGE AREA FILTERED ARC DEPOSITION OF CARBON AND BORON BASED HARD COATINGS  

DOE Green Energy (OSTI)

This document is a final report covering work performed under Contract No. DE-FG02-99ER82911 from the Department of Energy under a SBIR Phase II Program. Wear resistant, hard coatings can play a vital role in many engineering applications. The primary goal of this project was to develop coatings containing boron and carbon with hardness greater than 30 GPa and evaluate these coatings for machining applications. UES has developed a number of carbon and boron containing coatings with hardness in the range of 34 to 65 GPa using a combination of filtered cathodic arc and magnetron sputtering. The boron containing coatings were based on TiB2, TiBN, and TiBCN, while the carbon containing coatings ere TiC+C and hydrogen free diamond-like-carbon. Machining tests were performed with single and multilayer coated tools. The turning and milling tests were run at TechSolve Inc., under a subcontract at Ohio State University. Significant increases in tool lives were realized in end milling of H-13 die steel (8X) and titanium alloy (80%) using the TiBN coating. A multilayer TiBN/TiN performed the best in end-milling of highly abrasive Al-Si alloys. A 40% increase in life over the TiAlN benchmark coating was found. Further evaluations of these coatings with commercialization partners are currently in progress.

Bhattacharya, Rabi S.

2003-12-05T23:59:59.000Z

311

Stability of very-high pressure arc discharges against perturbations of the electron temperature  

Science Conference Proceedings (OSTI)

We study the stability of the energy balance of the electron gas in very high-pressure plasmas against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion equation, we apply the model to a very high-pressure (100 bar) xenon plasma and find instability for electron temperatures, T{sub e}, in a window between 2400 K and 5500-7000 K x 10{sup 3} K, depending on the current density (10{sup 6}-10{sup 8} A/m{sup 2}). The instability can be traced back to the Joule heating of the electron gas being a growing function of T{sub e}, which is due to a rising dependence of the electron-atom collision frequency on T{sub e}. We then analyze the T{sub e} range occurring in very high-pressure xenon lamps and conclude that only the near-anode region exhibits T{sub e} sufficiently low for this instability to occur. Indeed, previous experiments have revealed that such lamps develop, under certain conditions, voltage oscillations accompanied by electromagnetic interference, and this instability has been pinned down to the plasma-anode interaction. A relation between the mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is discussed.

Benilov, M. S. [Departamento de Fisica, Ciencias Exactas e Engenharia, Universidade da Madeira, Largo do Municipio, Funchal 9000 (Portugal); Hechtfischer, U. [Philips Lighting, BU Automotive Lamps, Technology, Philipsstrasse 8, Aachen 52068 (Germany)

2012-04-01T23:59:59.000Z

312

Argonne's HigH THrougHpuT reseArcH LAborATory  

NLE Websites -- All DOE Office Websites (Extended Search)

accelerating materials innovation accelerating materials innovation Argonne's HigH THrougHpuT reseArcH LAborATory The conventional "one-at-a-time" sequential approach for synthesizing, characterizing and evaluating new materials typically provides only incremental improvements; it is both labor- and resource-intensive as well as very expensive. T h e d is c o v e r y a n d s y n t h e s is o f n e w m a t e r ia ls a r e c r it ic a l b o t t le n e c k s in t h e s e a r c h f o r a lt e r n a t iv e e n e r g y s o u r c e s . Argonne nATionAL LAborATory's High Throughput research Laboratory accelerates the discovery and optimization of new materials, leading to "quantum jump" improvements and fast-tracked marketplace entry. Argonne's HTR provides highly automated and parallel approaches to materials development. This allows scientists to

313

Departures from local thermodynamic equilibrium in cutting arc plasmas derived from electron and gas density measurements using a two-wavelength quantitative Schlieren technique  

SciTech Connect

A two-wavelength quantitative Schlieren technique that allows inferring the electron and gas densities of axisymmetric arc plasmas without imposing any assumption regarding statistical equilibrium models is reported. This technique was applied to the study of local thermodynamic equilibrium (LTE) departures within the core of a 30 A high-energy density cutting arc. In order to derive the electron and heavy particle temperatures from the inferred density profiles, a generalized two-temperature Saha equation together with the plasma equation of state and the quasineutrality condition were employed. Factors such as arc fluctuations that influence the accuracy of the measurements and the validity of the assumptions used to derive the plasma species temperature were considered. Significant deviations from chemical equilibrium as well as kinetic equilibrium were found at elevated electron temperatures and gas densities toward the arc core edge. An electron temperature profile nearly constant through the arc core with a value of about 14000-15000 K, well decoupled from the heavy particle temperature of about 1500 K at the arc core edge, was inferred.

Prevosto, L.; Mancinelli, B. [Grupo de Descargas Electricas, Departamento Ing. Electromecanica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto 2600, Santa Fe (Argentina); Artana, G. [Laboratorio de Fluidodinamica, Departamento Ing. Mecanica, Facultad de Ingenieria (UBA), Paseo Colon 850, C1063ACV, Buenos Aires (Argentina); Kelly, H. [Grupo de Descargas Electricas, Departamento Ing. Electromecanica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto 2600, Santa Fe (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales (UBA), Instituto de Fisica del Plasma (CONICET), Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina)

2011-03-15T23:59:59.000Z

314

DYNAMICAL PROPERTIES OF s-d INTERACTION  

SciTech Connect

The dynamical propertics of two spin systems composed of conduction electron spins and localized d-spins interacting by exchange are investigated in connection with the electron-spin resonance of d-spins with the free electron g- value. It seems that some basic considerations are necessary for the problem along the line of the widely accepted idea thai the s-d interaction itself does not lead to any relaxation time and shift. The usual adiahatic approximation is applied to this idea. A modified damping equation of the Bloch type as well as Bloch's relaxation theory arc also useful, but these are not enough for a complete solution of the problem. A certain controversy involved in recent experimental and theoretical work at Berkeley concerning the electron spin resonance in Cu-Mu dilute alloy is pointed out and examined. It appears that the possibility could not be eliminated that the spin-lattice relaxation time of conduction electrons in the alloy due to mechanisms other than the s-d interaction is longer than previous authors have assumed. (auth)

Hasegawa, H.

1959-04-01T23:59:59.000Z

315

Drum-boiler dynamics  

Science Conference Proceedings (OSTI)

A nonlinear dynamic model for natural circulation drum-boilers is presented. The model describes the complicated dynamics of the drum, downcomer, and riser components. It is derived from first principles, and is characterized by a few physical parameters. ...

K. J. íStröM; R. D. Bell

2000-03-01T23:59:59.000Z

316

Dynamic Residential Window prototype  

NLE Websites -- All DOE Office Websites (Extended Search)

to have dynamic seasonal solar control: high solar gains in the winter with high insulation and low solar gains in the summer. Dynamic, high performance products can be based...

317

General Dynamics, Electric Boat  

Science Conference Proceedings (OSTI)

General Dynamics, Electric Boat. NVLAP Lab Code: 100560-0. Address and Contact Information: 75 Eastern Point Road ...

2013-08-16T23:59:59.000Z

318

NIST Photovoltaic carrier dynamics  

Science Conference Proceedings (OSTI)

... carrier dynamics in novel electronic photovoltaic materials being considered and developed for future solar cell and energy capture applications. ...

2013-04-01T23:59:59.000Z

319

Langevin molecular dynamics derived from Ehrenfest dynamics  

E-Print Network (OSTI)

Stochastic Langevin molecular dynamics for nuclei is derived from quantum classical molecular dynamics, also called Ehrenfest dynamics, at positive temperature, assuming that the molecular bulk system is in equilibrium and that the initial data for the electrons is stochastically perturbed from the ground state. The initial electron probability distribution is derived from the Liouville equilibrium solution generated by the nuclei acting as a heat bath for the electrons. The diffusion and friction coefficients in the Langevin equation satisfy Einstein's fluctuation-dissipation relation. The fluctuating initial data yields, in addition to the fluctuating diffusion terms, also a contribution to the drift, modifying the standard ab initio Born-Oppenheimer solution at zero temperature, where the electrons are in their ground state for the current nuclear configuration. The dissipative friction mechanism comes from the evolution of the electron ground state, due to slow dynamics of the nuclei, while the modified d...

Szepessy, Anders

2007-01-01T23:59:59.000Z

320

AVESTAR® - Dynamic Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Modeling Dynamic Modeling The AVESTAR team is pursuing research on the dynamic modeling and simulation of advanced energy systems ranging from power plants to power grids. Dynamic models provide a continuous view of energy systems in action by calculating their transient behavior over time. Plant-wide Models For power plants, dynamic models are used to analyze a wide variety of operating scenarios, including normal base load operation, startup, shutdown, feedstock switchovers, cycling, and load-following. Dynamic process and control models are also essential for analyzing plant responses to setpoint changes and disturbances, as well as malfunctions and abnormal situations. Other applications of plant-wide dynamic models include controllability and operational flexibility analyses, environmental studies, safety evaluations, and risk mitigation.

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Tunable, self-powered integrated arc plasma-melter vitrification system for waste treatment and resource recovery  

DOE Patents (OSTI)

The present invention provides a relatively compact self-powered, tunable waste conversion system and apparatus which has the advantage of highly robust operation which provides complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The system provides the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or by an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material. In the preferred embodiment of the invention, the arc plasma furnace and joule heated melter are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The preferred configuration of this embodiment of the invention utilizes two arc plasma electrodes with an elongated chamber for the molten pool such that the molten pool is capable of providing conducting paths between electrodes. The apparatus may additionally be employed with reduced or without further use of the gases generated by the conversion process. The apparatus may be employed as a self-powered or net electricity producing unit where use of an auxiliary fuel provides the required level of electricity production.

Titus, Charles H. (Newtown Square, PA); Cohn, Daniel R. (Chestnuthill, MA); Surma, Jeffrey E. (Kennewick, WA)

1998-01-01T23:59:59.000Z

322

Dosimetric comparison of volumetric modulated Arc therapy, step-and-shoot, and sliding window IMRT for prostate cancer  

Science Conference Proceedings (OSTI)

This study aims to evaluate treatment plans generated by Step-and-Shoot (SS), Sliding Window (SW) and Volumetric Modulated Arc Therapy (VMAT) in order to assess the differences in dose volume histograms of planning target volume (PTV) and organs at risk (OAR), conformity indices, radiobiological evaluations, and plan quality for prostate cancer cases. Six prostate cancer patients treated in our center were selected for this retrospective study. Treatment plans were generated with Eclipse version 8.9 using 10 MV photon beams. For VMAT, Varian Rapid Arc with 1 or 2 arcs, and for SS and SW IMRT, 7-9 fields were used. Each plan had three PTVs with prescription doses of 81, 59.4, and 45 Gy to prostate, to prostate and lymph nodes, and to pelvis, respectively. Doses to PTV and OAR and the conformal indices (COIN) were compared among three techniques. The equivalent uniform dose (EUD), tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated and compared. The mean doses to the PTV prostate on average were 83 Gy and the percent differences of mean dose among all techniques were below 0.28. For bladder and rectum, the percent differences of mean dose among all techniques were below 2.2. The COIN did not favour any particular delivery method over the other. The TCP was higher with SS and SW for four patients and higher with VMAT for two patients. The NTCP for the rectum was the lowest with VMAT in five out of the six patients. The results show similar target coverage in general.

Schnell, Erich; De La Fuente Herman, Tania; Young, Julie; Hildebrand, Kim; Algan, Ozer; Syzek, Elizabeth; Herman, Terence; Ahmad, Salahuddin [Department of Radiation Oncology, University of Oklahoma Health Sciences Center 800 N.E. 10th St., OKCC L100, Oklahoma City, OK 73104 (United States)

2012-10-23T23:59:59.000Z

323

Removal of nitrogen oxides from a gas stream by using monatomic nitrogen induced by a pulsed arc  

DOE Green Energy (OSTI)

The effectiveness of N atoms, nitrogen, induced by a pulsed electric arc, in reducing nitric oxide (NO) and nitrogen dioxide (NO{sub 2}) was studied. Goal is reduction of nitrogen oxides (NO{sub x}) from automobile emissions by this alternative technique, which can be cost-effective and has the potential to reduce NO{sub x} in exhaust containing up to 10% oxygen. Initial tests with 100, 500, and 1,000 ppM NO in pure nitrogen have shown that a greater than 50% reduction of NO/NO{sub x} is readily achievable. At an NO concentration of 100 ppM, a greater than 90% NO/NO{sub x} reduction was recorded. Different flow rates of the monatomic nitrogen and the gas stream were tested. The flow rate of the monatomic nitrogen did not have a significant effect on the reduction efficiency, unlike the flow rate of the gas stream. The cross-sectional flow area of the gas stream was varied in order to assess whether the proximity of the gas stream to the arc would affect NO/NO{sub x} reduction. Results of the tests revealed that the smallest cross-sectional area had the best reduction, but also the highest chance of contacting the arc. The composition of the gas stream was also varied to elucidate the effects of N0{sub 2} and 0{sub 2} on the NO/NO{sub x} reduction efficiency. When N0{sub 2} and 0{sub 2} are present in the gas stream, both gases lower the reduction efficiency significantly by creating more NO or N0{sub 2}. Experiments are continuing to improve the reduction efficiency. The electrical power, a function of pulse frequency, voltage, and current, was treated as a key parameter in the investigation. The power consumption of the high-voltage purser apparatus for a 100-kW engine was estimated to be 3 kW.

Ng, H.K.; Novick, V.J.; Sekar, R.R. [Argonne National Lab., IL (United States); Pierucci, K.A. [Illinois Inst. of Tech., Chicago, IL (United States); Geise, M.F. [Notre Dame Univ., IN (United States)

1995-01-01T23:59:59.000Z

324

Mo-containing tetrahedral amorphous carbon deposited by dualfiltered cathodic vacuum arc with selective pulsed bias voltage  

SciTech Connect

Metal-containing tetrahedral amorphous carbon films were produced by dual filtered cathodic vacuum arc (FCVA) plasma sources operated in sequential pulsed mode. A negatively pulsed bias was applied to the substrate only when carbon plasma was generated. Films thickness was measured after deposition by profilometry. Glass slides with silver pads were used as substrate for the of the measurement sheet resistance. The microstructure and composition of the films were characterized by Raman spectroscopy and Rutherford backscattering, respectively. It found that the electrical resistivity decreases with an increase of the Mo content, which can be ascribed to an increase of sp2 content and an increase of the sp2 cluster size.

Pasaja, Nitisak; Sansongsiri, Sakon; Anders, Andre; Vilaithong,Thiraphat; Intasiri, Sawate

2006-09-10T23:59:59.000Z

325

Mo-containing tetrahedral amorphous carbon deposited by dualfiltered cathodic vacuum arc with selective pulsed bias voltage  

SciTech Connect

Metal-containing tetrahedral amorphous carbon films wereproduced by dual filtered cathodic vacuum arc plasma sources operatedinsequentially pulsed mode. Negatively pulsed bias was applied to thesubstrate when carbon plasma was generated, whereas it was absentwhen themolybdenum plasma was presented. Film thickness was measured afterdeposition by profilometry. Glass slides with silver padswere used assubstrates for the measurement of the sheet resistance. Themicrostructure and composition of the films were characterizedbyRamanspectroscopy and Rutherford backscattering, respectively. It was foundthat the electrical resistivity decreases with an increaseof the Mocontent, which can be ascribed to an increase of the sp2 content and anincrease of the sp2 cluster size.

Pasaja, Nitisak; Sansongsiri, Sakon; Intasiri, Sawate; Vilaithong, Thiraphat; Anders, Andre

2007-01-24T23:59:59.000Z

326

The Mobility and Grain Boundaries Study of Austenite-Ferrite ...  

Science Conference Proceedings (OSTI)

Atomic-Scale Modeling of the Mobility of Boundaries of Deformation Twins in .... Molecular-Dynamics Simulations and In-Situ Electron Microscopy Studies of ...

327

Integrating GIS with Distributed Applications Using Dynamic Data-Sharing Mechanisms  

Science Conference Proceedings (OSTI)

Effective integration of a stand-alone GIS (e.g., ArcView 3.x) into a complex distributed software application requires an efficient, reliable mechanism for passing data and function requests to and from the GIS component. This paper describes the use of dynamic data-sharing and inter-process communication mechanisms to integrate GIS capability into a multi-jurisdictional distributed emergency management information system. These mechanisms include dynamic layer updates from spatial and attribute information shared via a distributed relational database across multiple sites; storage of private and shared ViewMarks to facilitate consistent GIS views; and asynchronous inter-process communication using function queuing and a data sharing library.

Burnett, Robert A. (BATTELLE (PACIFIC NW LAB)); Tzemos, Spyridon (BATTELLE (PACIFIC NW LAB)); Stoops, LaMar R. (BATTELLE (PACIFIC NW LAB))

2002-08-21T23:59:59.000Z

328

Chemical Structure and Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

2154-3 2154-3 UC-400 Annual Report 2000 Chemical Structure and Dynamics Steven D. Colson, Associate Director Robin S. McDowell, Program Manager and the Staff of the Chemical Structure and Dynamics Program April 2001 Prepared for the U.S. Department of Energy under Contract DE-AC06-76RL01830 Chemical Structure and Dynamics 2000 Annual Report Contents Chemical Structure and Dynamics 2000 Annual Report Chemical Structure and Dynamics 2000 Annual Report 1. Introduction Chemical Structure and Dynamics Program......................................................... 1-3 2. Reaction Mechanisms at Liquid Interfaces Structure and Reactivity of Ice Surfaces and Interfaces G. A. Kimmel, Z. Dohnálek, K. P. Stevenson, R. S. Smith,

329

Dynamic Instruction Fusion  

E-Print Network (OSTI)

SANTA CRUZ DYNAMIC INSTRUCTION FUSION A thesis submitted in4 2.2 Instruction Fusion & Complex10 3.1 Fusion Selection

Lee, Ian

2012-01-01T23:59:59.000Z

330

Fundamentals of Dynamic Behavior  

Science Conference Proceedings (OSTI)

Feb 28, 2011 ... Atomistically-Informed Dislocation Dynamics Simulations of High Rate Deformation of Single fcc Crystals: Zhiqiang Wang1; 1University of North ...

331

Dynamic Windows.pdf  

NLE Websites -- All DOE Office Websites (Extended Search)

including products with improved fixed or static properties and products with dynamic solar heat gain proper- ties. Nine representative window products are examined in eight...

332

The effect of arc velocity on cold electrode erosion Alexei M. Essiptchouk,a)  

E-Print Network (OSTI)

of the radial redistribution of the gas due to centrifugal force in the vortex. Therefore the cold- est gas in air, for magnetic induction values B in the range of 0.005­0.386 T, axial air gas velocity of 7.65 ms displacement are used to diminish the erosion of the electrode: gas dynamic, i.e., application of vortex flow

Marotta, Aruy

333

Partial Dynamical Symmetry and Mixed Dynamics  

E-Print Network (OSTI)

Partial dynamical symmetry describes a situation in which some eigenstates have a symmetry which the quantum Hamiltonian does not share. This property is shown to have a classical analogue in which some tori in phase space are associated with a symmetry which the classical Hamiltonian does not share. A local analysis in the vicinity of these special tori reveals a neighbourhood of phase space foliated by tori. This clarifies the suppression of classical chaos associated with partial dynamical symmetry. The results are used to divide the states of a mixed system into ``chaotic'' and ``regular'' classes.

A. Leviatan; N. D. Whelan

1996-08-24T23:59:59.000Z

334

Narrow groove gas tungsten arc welding of ASTM A508 Class 4 steel for improved toughness properties  

Science Conference Proceedings (OSTI)

Welding of heavy section steel has traditionally used the automatic submerged arc welding (ASAW) process because of the high deposition rates achievable. However, the properties, particularly fracture toughness, of the weld are often inferior when compared to base material. This project evaluated the use of narrow groove gas tungsten arc welding (GTAW) to improve weld material properties. The welding procedures were developed for ASTM A508 Class 4 base material using a 1% Ni filler material complying to AWS Specification A.23-90-EF3-F3-N. A narrow groove joint preparation was used in conjunction with the GTAW process so competitive fabrication rates could be achieved when compared to the ASAW process. Weld procedures were developed to refine weld substructure to achieve better mechanical properties. Two heaters of weld wire were used to examine the effects of minor filler metal chemistry differences on weld mechanical properties. Extensive metallographic evaluations showed excellent weld quality with a refined microstructure. Chemical analysis of the weld metal showed minimal weld dilution by the base metal. Mechanical testing included bend and tensile tests to ensure weld quality and strength. A Charpy impact energy curve versus temperature and fracture toughness curve versus temperature were developed for each weld wire heat. Results of fracture toughness and Charpy impact testing indicated an improved transition temperature closer to that of the base material properties.

Penik, M.A. Jr. [Rensselaer Polytechnic Inst., Troy, NY (United States)

1997-04-01T23:59:59.000Z

335

Effect of ion mass and charge state on transport of vacuum ARC plasmas through a biased magnetic filter  

Science Conference Proceedings (OSTI)

The effect of ion mass and charge state on plasma transport through a 90{sup o}-curved magnetic filter is experimentally investigated using a pulsed cathodic arc source. Graphite, copper, and tungsten were selected as test materials. The filter was a bent copper coil biased via the voltage drop across a low-ohm, ''self-bias'' resistor. Ion transport is accomplished via a guiding electric field, whose potential forms a ''trough'' shaped by the magnetic guiding field of the filter coil. Evaluation was done by measuring the filtered ion current and determination of the particle system coefficient, which can be defined as the ratio of filter ion current, divided by the mean ion charge state, to the arc current. It was found that the ion current and particle system coefficient decreased as the mass-to-charge ratio of ions increased. This result can be qualitatively interpreted by a very simply model of ion transport that is based on compensation of the centrifugal force by the electric force associated with the guiding potential trough.

Byon, Eungsun; Kim, Jong-Kuk; Kwon, Sik-Chol; Anders, Andre

2003-12-01T23:59:59.000Z

336

Recycling of rubber tires in electric arc furnace steelmaking: simultaneous combustion of metallurgical coke and rubber tyres blends  

Science Conference Proceedings (OSTI)

The present study investigates the effect of addition of waste rubber tires on the combustion behavior of its blends with coke for carbon injection in electric arc furnace steelmaking. Waste rubber tires were mixed in different proportions with metallurgical coke (MC) (10:90, 20:80, 30:70) for combustion and pyrolysis at 1473 K in a drop tube furnace (DTF) and thermogravimetric analyzer (TGA), respectively. Under experimental conditions most of the rubber blends indicated higher combustion efficiencies compared to those of the constituent coke. In the early stage of combustion the weight loss rate of the blends is much faster compared to that of the raw coke due to the higher volatile yield of rubber. The presence of rubber in the blends may have had an impact upon the structure during the release and combustion of their high volatile matter (VM) and hence increased char burnout. Measurements of micropore surface area and bulk density of the chars collected after combustion support the higher combustion efficiency of the blends in comparison to coke alone. The surface morphology of the 30% rubber blend revealed pores in the residual char that might be attributed to volatile evolution during high temperature reaction in oxygen atmosphere. Physical properties and VM appear to have a major effect upon the measured combustion efficiency of rubber blends. The study demonstrates that waste rubber tires can be successfully co-injected with metallurgical coke in electric arc furnace steelmaking process to provide additional energy from combustion. 44 refs., 11 figs., 2 tabs.

Magdalena Zaharia; Veena Sahajwalla; Byong-Chul Kim; Rita Khanna; N. Saha-Chaudhury; Paul O'Kane; Jonathan Dicker; Catherine Skidmore; David Knights [University of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering

2009-05-15T23:59:59.000Z

337

Towards dynamic collaboration architectures  

Science Conference Proceedings (OSTI)

In this paper, we introduce the concept of dynamically changing between centralized, replicated, and hybrid collaboration architectures. It is implemented by providing users a function that dynamically changes the mapping between user-interface and program ... Keywords: ad-hoc collaboration, application sharing, collaboration architecture, latecomers, mobile collaboration

Goopeel Chung; Prasun Dewan

2004-11-01T23:59:59.000Z

338

Langevin molecular dynamics derived from Ehrenfest dynamics  

E-Print Network (OSTI)

Stochastic Langevin molecular dynamics for nuclei is derived from the Ehrenfest Hamiltonian system (also called quantum classical molecular dynamics) in a Kac-Zwanzig setting, with the initial data for the electrons stochastically perturbed from the ground state and the ratio, $M$, of nuclei and electron mass tending to infinity. The Ehrenfest nuclei dynamics is approximated by the Langevin dynamics with accuracy $o(M^{-1/2})$ on bounded time intervals and by $o(1)$ on unbounded time intervals, which makes the small $\\mathcal{O}(M^{-1/2})$ friction and $o(M^{-1/2})$ diffusion terms visible. The initial electron probability distribution is a Gibbs density at low temperture, derived by a stability and consistency argument: starting with any equilibrium measure of the Ehrenfest Hamiltonian system, the initial electron distribution is sampled from the equilibrium measure conditioned on the nuclei positions, which after long time leads to the nuclei positions in a Gibbs distribution (i.e. asymptotic stability); by consistency the original equilibrium measure is then a Gibbs measure.The diffusion and friction coefficients in the Langevin equation satisfy the Einstein's fluctuation-dissipation relation.

Anders Szepessy

2007-12-21T23:59:59.000Z

339

Solar Dynamics | Open Energy Information  

Open Energy Info (EERE)

Dynamics Jump to: navigation, search Name Solar Dynamics Place Ottumwa, Iowa Zip IA 52501 Sector Solar Product Solar Dynamics is a US-based solar powered attic roof vents...

340

Dosimetric research on intensity-modulated arc radiotherapy planning for left breast cancer after breast-preservation surgery  

Science Conference Proceedings (OSTI)

Intensity-modulated radiotherapy (IMRT) has played an important role in breast cancer radiotherapy after breast-preservation surgery. Our aim was to study the dosimetric and implementation features/feasibility between IMRT and intensity-modulated arc radiotherapy (Varian RapidArc, Varian, Palo Alto, CA). The forward IMRT plan (f-IMRT), the inverse IMRT, and the RapidArc plan (RA) were generated for 10 patients. Afterward, we compared the target dose distribution of the 3 plans, radiation dose on organs at risk, monitor units, and treatment time. All 3 plans met clinical requirements, with RA performing best in target conformity. In target homogeneity, there was no statistical significance between RA and IMRT, but both of homogeneity were less than f-IMRT's. With regard to the V{sub 5} and V{sub 10} of the left lung, those in RA were higher than in f-IMRT but were lower than in IMRT; for V{sub 20} and V{sub 30}, the lowest was observed in RA; and in the V{sub 5} and V{sub 10} of the right lung, as well as the mean dose in normal-side breast and right lung, there was no statistically significance difference between RA and IMRT, and the lowest value was observed in f-IMRT. As for the maximum dose in the normal-side breast, the lowest value was observed in RA. Regarding monitor units (MUs), those in RA were higher than in f-IMRT but were lower than in IMRT. Treatment time of RA was 84.6% and 88.23% shorter than f-IMRT and IMRT, respectively, on average. Compared with f-IMRT and IMRT, RA performed better in target conformity and can reduce high-dose volume in the heart and left lung-which are related to complications-significantly shortening treatment time as well. Compared with IMRT, RA can also significantly reduce low-dose volume and MUs of the afflicted lung.

Yin Yong, E-mail: yinyongsd@yahoo.com.cn [School of Information Science and Engineering, Shandong University, Ji'nan (China); Department of Radiation Oncology, Shandong Cancer Hospital, Shandong Academy of Medical Scienses, Shandong Provincial Key Laboratory of Radiation Oncology (China); Chen Jinhu; Sun Tao; Ma Changsheng; Lu Jie; Liu Tonghai [Department of Radiation Oncology, Shandong Cancer Hospital, Shandong Academy of Medical Scienses, Shandong Provincial Key Laboratory of Radiation Oncology (China); Wang Ruozheng [Department of Radiation Oncology, Xinjiang Medical University, Affiliated Hospital, Urumchi (China)

2012-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Dynamic Behavior of Materials V  

Science Conference Proceedings (OSTI)

Dynamic Characterization of Cast and Wrought Uranium-Niobium Metals · Dynamic Deformation Response of High-Strength Ni-Containing Steels.

342

Experimental and theoretical study of exhaust gas fuel reforming of Diesel fuel by a non-thermal arc discharge for syngas production  

E-Print Network (OSTI)

-thermal arc discharge for syngas production A. Lebouvier1,2 , F. Fresnet2 , F. Fabry1 , V. Boch2 , V. Rohani1% and a conversion rate of 95% have been reached which correspond to a syngas dry molar fraction of 25%. For the most and promote H2O and CO2 production. Keywords: Plasma reformer, syngas, diesel fuel reforming, NOx trap. 1

Paris-Sud XI, Université de

343

Cirrus Outflow Dynamics  

Science Conference Proceedings (OSTI)

Cirrus outflow from deep convection are analyzed as dynamically and thermodynamically active systems. The initial outflow is considered as an analog to wake collapse, in which a neutrally buoyant flow intrusion is flattened and stretched by its ...

Douglas K. Lilly

1988-05-01T23:59:59.000Z

344

WORKSHOP ON NUCLEAR DYNAMICS  

E-Print Network (OSTI)

Complete Events in Medium-Energy Nuclear Collisions" C-Y.+ corrections. (A) The nuclear potential-energy problem isquantum dynamics in high-energy nuclear collisions. We have

Myers, W.D.

2010-01-01T23:59:59.000Z

345

Optical dynamic circuit services  

Science Conference Proceedings (OSTI)

IP service, leased-line service and POTS service have been the three long-standing communication service offerings of providers. Recently, both commercial and research-andeducation network providers have started offering optical dynamic circuit services. ...

Malathi Veeraraghavan; Mark Karol; George Clapp

2010-11-01T23:59:59.000Z

346

A Molecular Dynamics Simulation  

Science Conference Proceedings (OSTI)

Ab Initio Local Energy and Local Stress Calculations: Applications to Materials ... Computational Fluid Dynamics and Experimental Results for the Horizontal .... Films and Applications to a New Generation of Multifunctional Devices/Systems.

347

A Molecular Dynamics  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

348

A Molecular Dynamic Study  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

349

Frontal Geostrophic Dynamics  

Science Conference Proceedings (OSTI)

From the primitive equations simplified dynamics are derived that apply to frontal situations in which interface slopes are important. The formalism, which eliminates inertial motions, is not Unlike the derivation of the quasi-geostrophic ...

Benoit Cushman-Roisin

1986-01-01T23:59:59.000Z

350

Investigation of the effect of welding parameters on weld quality of plasma arc keyhole welding of structural steels  

SciTech Connect

In the present investigation, the individual and interactive effects of the main welding parameters on weld quality of plasma arc keyhole welding of conventional structural steel, high strength microalloyed steel and strong formable microalloyed steel have been examined using welding of butt joints with a square groove in various welding positions, and welding of joint roots with a single-V-groove and the root face in the flat position. The most important welding parameters are welding current, welding speed and welding gases, especially plasma gas flow rate. Welding parameter combinations producing the best quality welds are presented. It is shown that it is possible to achieve defect-free high-quality welds with good strength and toughness properties, but the allowable range of variation of welding parameters, especially for the highest weld quality, is narrow. An argonhydrogen mixture for the plasma gas together with argon as shielding and backing gases give the best results with respect to weld quality.

Martikainen, J.K.; Moisio, T.J.I. (Lappeenranta Univ. of Technology, Lappeenranta (Finland). Welding Technology Lab.)

1993-07-01T23:59:59.000Z

351

Circuit breaker model for digital simulation based on Mayr`s and Cassie`s differential arc equations  

Science Conference Proceedings (OSTI)

A model of a circuit breaker for digital simulation programs based on the Mayr`s and Cassie`s differential arc equations was developed. The model can be used to determine the current interruption capability of the circuit breaker. The theoretical basis and the structure of the model are described. The model is verified on a sample of measured results, and the use of the model for practical application is demonstrated. Although the validation of the model is limited to the vicinity of current zero, it can be usefully used. Its advantage lies in the fact, that the simulation programs set and solve the system of breaker and network differential equations. Calculation of a breaker capability can so be done using a complex network.

Bizjak, G.; Zunko, P. [Univ. of Ljubljana (Slovenia). Faculty for Electrical and Computer Engineering; Povh, D. [Siemens AG, Erlangen (Germany)

1995-07-01T23:59:59.000Z

352

High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition  

Science Conference Proceedings (OSTI)

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

Anders, Andre; Lim, Sunnie H.N.; Yu, Kin Man; Andersson, Joakim; Rosen, Johanna; McFarland, Mike; Brown, Jeff

2009-04-24T23:59:59.000Z

353

Industrial harmonic analysis system for magnetic measurements of SSC collider arc and high energy booster corrector magnets  

Science Conference Proceedings (OSTI)

The SSCL collider arc and high energy booster corrector magnets are 50 mm bore cryogenic magnets. The integral strength and harmonics will be measured by industry at full current at 4.2 K and at plus and minus 400 mA at room temperature. Dipoles, quadrupoles, and sextupoles have error tolerances of a few tens of units. A prototype harmonic analysis system for magnetic measurements of production and prototype dipole, quadrupole and sextupole magnets has been designed and is being fabricated. We describe the criteria for search coil designs, data acquisition system hardware and software. Radial search coil arrays are being fabricated utilizing multifilar wire. Two digital integrators will allow simultaneous accumulation of unbucked and bucked configurations.

Green, M.I.; Sponsel, R.; Sylvester, C.

1993-05-01T23:59:59.000Z

354

The Symposium Imaging of Dynamic Processes: Multimedia Highlights  

Science Conference Proceedings (OSTI)

“Increased Understanding of Gas Atomization from Gas Flow Imaging and High .... A technique for imaging the solid-liquid interface in gas-tungsten-arc welds at

355

Dynamic manipulability of multifingered grasping  

Science Conference Proceedings (OSTI)

In this paper, we extend the concept of dynamic manipulability to evaluate the dynamic property of multifingered grasping systems consisting of amultifingered hand and a grasped object, and propose a measure of dynamic manipulability of multifingered ... Keywords: dynamic manipulability, grasping, internal force, multifingered hand, omnidirectionality

Yasuyoshi Yokokohji; Jose San Martin; Masaki Fujiwara

2009-08-01T23:59:59.000Z

356

The Dynamical Discrete Web  

E-Print Network (OSTI)

The dynamical discrete web (DDW), introduced in recent work of Howitt and Warren, is a system of coalescing simple symmetric one-dimensional random walks which evolve in an extra continuous dynamical parameter s. The evolution is by independent updating of the underlying Bernoulli variables indexed by discrete space-time that define the discrete web at any fixed s. In this paper, we study the existence of exceptional (random) values of s where the paths of the web do not behave like usual random walks and the Hausdorff dimension of the set of such exceptional s. Our results are motivated by those about exceptional times for dynamical percolation in high dimension by H\\"aggstrom, Peres and Steif, and in dimension two by Schramm and Steif. The exceptional behavior of the walks in DDW is rather different from the situation for dynamical random walks of Benjamini, H\\"aggstrom, Peres and Steif. In particular, we prove that there are exceptional values of s for which the walk from the origin S^s(n) has limsup S^s(n)/\\sqrt n \\leq K with a nontrivial dependence of the Hausdorff dimension on K. We also discuss how these and other results extend to the dynamical Brownian web, a natural scaling limit of DDW. The scaling limit is the focus of a paper in preparation; it was studied by Howitt and Warren and is related to the Brownian net of Sun and Swart.

L. R. G. Fontes; C. M. Newman; K. Ravishankar; E. Schertzer

2007-04-20T23:59:59.000Z

357

Diamond-like atomic-scale composite films: Surface properties and stability studied by STM and AFM  

DOE Green Energy (OSTI)

Amorphous ``diamond-like/quartz-like`` composites a-(C:H/Si:O) and metal containing a-(C:H/Si:O/Me) constitute a novel class of diamond-related materials with a number of unique bulk and surface properties. In order to gain a more fundamental understanding of the surface properties and stability of these solids we have performed a scanning tunneling and atomic force microscopy investigation of both a-(C:H/Si:O) and a-(C:H/Si:O/Me) films, including the effects of ion bombardment and annealing.

Dorfman, B.; Abraizov, M. [SUNY, Farmingdale, NY (United States); Pollak, F.H. [CUNY, Brooklyn, NY (United States); Eby, R. [TopoMetrix, Bedminster, NJ (United States); Rong, Z.Y. [SUNY, Stony Brook, NY (United States); Strongin, M.; Yang, X.Q. [Brookhaven National Lab., Upton, NY (United States)

1995-10-01T23:59:59.000Z

358

PUBLISHED ONLINE: 20 NOVEMBER 2011 | DOI: 10.1038/NMAT3170 Atomic-scale transport in epitaxial graphene  

E-Print Network (OSTI)

* The high carrier mobility of graphene1­4 is key to its applications, and understanding the factors. The topography and graphene thicknesses are shown in Fig. 2a. Without applying a voltage between probes 1 and 3 graphene (STM bias voltage V = -0.05 V, tunnelling current I = 0.1 nA) showing a honeycomb structure

Perebeinos, Vasili

359

Atomic-Scale Structure of Al2O3-ZrO2 Mixed Oxides Prepared by Laser Ablation  

Science Conference Proceedings (OSTI)

By means of x-ray diffractometry (XRD) and X-ray absorption fine structure spectroscopy, the phase composition and atomic structure of laser evaporated ZrO2 and ZrO2-Al2O3 nanopowders have been studied. The results indicate that pure ZrO2 exists in the form of tetragonal structure, Al2O3 doped ZrO2 nanoparticles, however, have cubic structure. Compared to bulk tetragonal ZrO2, pure tetragonal ZrO2 nanoparticles have a shorter Zr-O- and Zr-Zr shell, indicating that the lattice contracts with decreasing particle size. For Al2O3 doped ZrO2 solid solution, the distances of first Zr-O and Zr-Zr (Al) coordination decrease with increasing solid solubility. The disorder degree of the ZrO2 lattice increases with increasing solid solubility. The coevaporated ZrO2-Al2O3 is quickly solidified into amorphous phase when it is ablated in a higher pressure. The amorphous phase contains Zr-O-Zr (Al) clusters and has shorter Zr-O distance and tower Zr-O coordination number.

Yang Xiuchun [College of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Dubiel, M. [Department of Physics, Martin Luther University of Halle, D-06108 Halle (Germany); Hofmeister, H. [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Riehemann, W. [Department of Materials Science and Engineering, Clausthal University of Technology (Germany)

2007-02-02T23:59:59.000Z

360

Surface Chemical Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Surface Chemical Dynamics Surface Chemical Dynamics The goal of the Surface Chemical Dynamics Program is to elucidate the underlying physical processes that determine the products (selectivity) and yield (efficiency) of chemical transformations relevant to energy-related chemistry on catalytic and nanostructured surfaces. Achieving this end requires understanding the evolution of the reactant-molecule/surface complex as molecules adsorb, bonds dissociate, surface species diffuse, new bonds form and products desorb. The pathways and time scales of these processes are ultimately determined by a multidimensional potential energy surface that is a function of the geometric and electronic structures of the surface and the reactant, product, intermediate and transition-state molecular and atomic species.

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

MAX Fluid Dynamics facility  

NLE Websites -- All DOE Office Websites (Extended Search)

MAX Fluid Dynamics facility MAX Fluid Dynamics facility Capabilities Engineering Experimentation Reactor Safety Testing and Analysis Overview Nuclear Reactor Severe Accident Experiments MAX NSTF SNAKE Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr MAX Fluid Dynamics facility Providing high resolution data for development of computational tools that model fluid flow and heat transfer within complex systems such as the core of a nuclear reactor. 1 2 3 4 5 Hot and cold air jets are mixed within a glass tank while laser-based anemometers and a high-speed infrared camera characterize fluid flow and heat transfer behavior. Click on image to view larger size image.

362

Substructured multibody molecular dynamics.  

SciTech Connect

We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

2006-11-01T23:59:59.000Z

363

Off-momentum dynamic aperture for lattices in the RHIC heavy ion runs  

Science Conference Proceedings (OSTI)

To reduce transverse emittance growth rates from intrabeam scattering in the RHIC heavy ion runs, a lattice with an increased phase advance in the arc FODO cells was adopted in 2008-2011. During these runs, a large beam loss due to limited off-momentum dynamic aperture was observed during longitudinal RF re-bucketing and with transverse cooling. Based on the beam loss observations in the previous ion runs and the calculated off-momentum apertures, we decided to adopt the lattice used before 2008 for the 2012 U-U and Cu-Au runs. The observed beam decay and the measured momentum aperture in the 2012 U-U run are presented.

Luo Y.; Bai, M.; Blaskiewicz, M.; Gu, X.; Fischer, W.; Marusic, A.; Roser, T.; Tepikian, S.; Zhang, S.

2012-05-20T23:59:59.000Z

364

Fractal Location and Anomalous Diffusion Dynamics for Oil Wells from the KY Geological Survey  

E-Print Network (OSTI)

Utilizing data available from the Kentucky Geonet (KYGeonet.ky.gov) the fossil fuel mining locations created by the Kentucky Geological Survey geo-locating oil and gas wells are mapped using ESRI ArcGIS in Kentucky single plain 1602 ft projection. This data was then exported into a spreadsheet showing latitude and longitude for each point to be used for modeling at different scales to determine the fractal dimension of the set. Following the porosity and diffusivity studies of Tarafdar and Roy1 we extract fractal dimensions of the fossil fuel mining locations and search for evidence of scaling laws for the set of deposits. The Levy index is used to determine a match to a statistical mechanically motivated generalized probability function for the wells. This probability distribution corresponds to a solution of a dynamical anomalous diffusion equation of fractional order that describes the Levy paths which can be solved in the diffusion limit by the Fox H function ansatz.

Andrew, Keith; Andrew, Kevin A

2009-01-01T23:59:59.000Z

365

Introduction to Accelerated Molecular Dynamics  

SciTech Connect

Molecular Dynamics is the numerical solution of the equations of motion of a set of atoms, given an interatomic potential V and some boundary and initial conditions. Molecular Dynamics is the largest scale model that gives unbiased dynamics [x(t),p(t)] in full atomistic detail. Molecular Dynamics: is simple; is 'exact' for classical dynamics (with respect to a given V); can be used to compute any (atomistic) thermodynamical or dynamical properties; naturally handles complexity -- the system does the right thing at the right time. The physics derives only from the interatomic potential.

Perez, Danny [Los Alamos National Laboratory

2012-07-10T23:59:59.000Z

366

Introduction to Accelerated Molecular Dynamics  

SciTech Connect

Molecular Dynamics is the numerical solution of the equations of motion of a set of atoms, given an interatomic potential V and some boundary and initial conditions. Molecular Dynamics is the largest scale model that gives unbiased dynamics [x(t),p(t)] in full atomistic detail. Molecular Dynamics: is simple; is 'exact' for classical dynamics (with respect to a given V); can be used to compute any (atomistic) thermodynamical or dynamical properties; naturally handles complexity -- the system does the right thing at the right time. The physics derives only from the interatomic potential.

Perez, Danny [Los Alamos National Laboratory

2012-07-10T23:59:59.000Z

367

An Ocean Dynamical Thermostat  

Science Conference Proceedings (OSTI)

The role of ocean dynamics in the regulation of tropical sea surface temperatures (SSTs) is investigated using the Zebiak-Cane coupled occan-atmosphere model. The model is forced with a uniform heating, or cooling, varying between ±40 W m?2 into ...

Amy C. Clement; Richard Seager; Mark A. Cane; Stephen E. Zebiak

1996-09-01T23:59:59.000Z

368

Neutron Scattering and Dynamics  

Science Conference Proceedings (OSTI)

... "Molecule" H2O (N2)0.8(O2)0.2 Al Cd sigma_s barn 168.3 20.1 1.5 6.5 ... 31 Collective dynamics Animation courtesy of A. Zheludev (ORNL) ...

2009-09-15T23:59:59.000Z

369

Tropical Cyclone Eye Dynamics  

Science Conference Proceedings (OSTI)

A new perspective of the dynamics of a tropical cyclone eye is given in which eye subsidence and the adiabatic warming accompanying it are accounted for directly from the equations of motion. Subsidence is driven by an adverse, axial gradient of ...

R. K. Smith

1980-06-01T23:59:59.000Z

370

Bütschli dynamic droplet system  

Science Conference Proceedings (OSTI)

Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Bütschli water-in-oil droplets as a model ... Keywords: Otto Bütschli, architecture, droplet, living technology, olive oil, origins of life

Rachel Armstrong; Martin Hanczyc

2013-10-01T23:59:59.000Z

371

BLOWER SYSTEM DYNAMICS  

SciTech Connect

An analysis is presented of the dynamics of a turboblower acting together with its connecting circuit. This is to be distinguished from the aero- thermodynamics involved in the design of the blower itself. The effect on system stability of blower and circuit characteristics is discussed. (auth)

Furgerson, W.T.

1958-04-16T23:59:59.000Z

372

Entanglement dynamics during decoherence  

Science Conference Proceedings (OSTI)

The evolution of the entanglement between oscillators that interact with the same environment displays highly non-trivial behavior in the long time regime. When the oscillators only interact through the environment, three dynamical phases were identified ... Keywords: 03.65.Yz, 03.67.Bg, 03.67.Mn, 05.40.Jc, Decoherence, Entanglement, Quantum Brownian Motion

Juan Pablo Paz; Augusto J. Roncaglia

2009-12-01T23:59:59.000Z

373

Dosimetric Impact of Using the Acuros XB Algorithm for Intensity Modulated Radiation Therapy and RapidArc Planning in Nasopharyngeal Carcinomas  

SciTech Connect

Purpose: To assess the dosimetric implications for the intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy with RapidArc (RA) of nasopharyngeal carcinomas (NPC) due to the use of the Acuros XB (AXB) algorithm versus the anisotropic analytical algorithm (AAA). Methods and Materials: Nine-field sliding window IMRT and triple-arc RA plans produced for 12 patients with NPC using AAA were recalculated using AXB. The dose distributions to multiple planning target volumes (PTVs) with different prescribed doses and critical organs were compared. The PTVs were separated into components in bone, air, and tissue. The change of doses by AXB due to air and bone, and the variation of the amount of dose changes with number of fields was also studied using simple geometric phantoms. Results: Using AXB instead of AAA, the averaged mean dose to PTV{sub 70} (70 Gy was prescribed to PTV{sub 70}) was found to be 0.9% and 1.2% lower for IMRT and RA, respectively. It was approximately 1% lower in tissue, 2% lower in bone, and 1% higher in air. The averaged minimum dose to PTV{sub 70} in bone was approximately 4% lower for both IMRT and RA, whereas it was approximately 1.5% lower for PTV{sub 70} in tissue. The decrease in target doses estimated by AXB was mostly contributed from the presence of bone, less from tissue, and none from air. A similar trend was observed for PTV{sub 60} (60 Gy was prescribed to PTV{sub 60}). The doses to most serial organs were found to be 1% to 3% lower and to other organs 4% to 10% lower for both techniques. Conclusions: The use of the AXB algorithm is highly recommended for IMRT and RapidArc planning for NPC cases.

Kan, Monica W.K., E-mail: kanwkm@ha.org.hk [Department of Oncology, Princess Margaret Hospital, Hong Kong (Hong Kong); Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (Hong Kong); Leung, Lucullus H.T. [Department of Oncology, Princess Margaret Hospital, Hong Kong (Hong Kong)] [Department of Oncology, Princess Margaret Hospital, Hong Kong (Hong Kong); Yu, Peter K.N. [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (Hong Kong)] [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (Hong Kong)

2013-01-01T23:59:59.000Z

374

Can volumetric modulated arc therapy with flattening filter free beams play a role in stereotactic body radiotherapy for liver lesions? A volume-based analysis  

SciTech Connect

Purpose: To compare volumetric modulated arc therapy with flattening filter free (FFF) and flattening filter (FF) beams in patients with hepatic metastases subject to hypofractionated radiotherapy (RT). Methods: A planning study on 13 virtual lesions of increasing volume was performed. Two single arc plans were optimized with the RapidArc technique using either FFF or FF beams. A second planning study was performed on ten patients treated for liver metastases to validate conclusions. In all cases, a dose of 75 Gy in 3 fractions was prescribed to the planning target volume (PTV) and plans were evaluated in terms of coverage, homogeneity, conformity, mean dose to healthy liver and to healthy tissue. For each parameter, results were expressed in relative terms as the percentage ratio between FFF and FF data. Results: In terms of PTV coverage, conformity index favored FFF for targets of intermediate size while FF resulted more suitable for small (<100 cm{sup 3}) and large (>300 cm{sup 3}) targets. Plans optimized with FFF beams resulted in increased sparing of healthy tissue in {approx_equal}85% of cases. Despite the qualitative results, no statistically significant differences were found between FFF and FF results. Plans optimized with un-flattened beams resulted in higher average MU/Gy than plans with FF beams. A remarkable and significant difference was observed in the beam-on time (BOT) needed to deliver plans. The BOT for FF plans was 8.2 {+-} 1.0 min; for FFF plans BOT was 2.2 {+-} 0.2 min. Conclusions: RapidArc plans optimized using FFF were dosimetrically equivalent to those optimized using FF beams, showing the feasibility of SBRT treatments with FFF beams. Some improvement in healthy tissue sparing was observed when using the FFF modality due to the different beam's profile. The main advantage was a considerable reduction of beam-on time, relevant for SBRT techniques.

Reggiori, Giacomo; Mancosu, Pietro; Castiglioni, Simona; Alongi, Filippo; Pellegrini, Chiara; Lobefalo, Francesca; Catalano, Maddalena; Fogliata, Antonella; Arcangeli, Stefano; Navarria, Piera; Cozzi, Luca; Scorsetti, Marta [IRCCS Istituto Clinico Humanitas, 20089 Rozzano (Milano) (Italy); Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); IRCCS Istituto Clinico Humanitas, 20089 Rozzano (Milano) (Italy); Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); IRCCS Istituto Clinico Humanitas, 20089 Rozzano (Milano) (Italy)

2012-02-15T23:59:59.000Z

375

The influence of the external circuit on arc-discharge of a spark-gap: Its application to a pulsed gas laser  

SciTech Connect

An investigation of the influence of the driving circuit on the arc-discharge of a spark-gap takes place in this work. The two most common types of circuits used in pulsed gas lasers have been studied for all possible combinations of capacitance allocation. In these circuits the spark-gap is used as ignition system and participates in the electric circuit through its resistance and inductance. This consideration shows that capacitances act as charge containers and feed the arc-discharge in the spark-gap independently of their positions in the circuit. Their values influence the total charge contained in the arc-discharge and this, in its turn, influences the discharge resistance. On the other hand, total charge flows through the discharge at a rate determined by the coupling of the circuit loops, namely, by the circuit type. Thus, circuit type influences the drift velocity and this, in its turn, influences the channel radius, which determines the discharge inductance.

Persephonis, P.; Giannetas, V.; Georgiades, C.; Parthenios, J.; Ioannou, A. [Univ. of Patras (Greece). Dept. of Physics

1995-03-01T23:59:59.000Z

376

Stratigraphy, petrology, and geochemistry of the Spurr Volcanic Complex, eastern Aleutian Arc, Alaska. [(Appendix for geothermal fluid chemistry)  

DOE Green Energy (OSTI)

The Spurr Volcanic Complex (SVC) is a calcalkaline, medium-K, sequence of andesites erupted over the last quarter of a million years by the easternmost currently active volcanic center in the Aleutian Arc. The ancestral Mt. Spurr was built mostly of andesites of uniform composition (58 to 60% SiO/sub 2/), although andesite production was episodically interrupted by the introduction of new batches of more mafic magma. Near the end of the Pleistocene the ancestral Mt. Spurr underwent Bezyianny-type avalanche caldera formation, resulting in the production of a volcanic debris avalanche with overlying ashflows. Immediately afterward, a large dome (the present Mt. Spurr) was emplaced in the caldera. Both the ashflows and dome are made of acid andesite more silicic than any analyzed lavas from the ancestral Mt. Spurr (60 to 63% SiO/sub 2/), yet contain olivine and amphibole xenocrysts derived from more mafic magma. The mafic magma (53 to 57% SiO/sub 2/) erupted during and after dome emplacement, forming proto-Crater Peak and Crater Peak. Hybrid pyroclastic flows and lavas were also produced. Proto-Crater Peak underwent glacial dissection prior to the formation of Crater Peak in approximately the same location. Appendices II through VIII contain a summary of mineral compositions; Appendix I contains geochemical data. Appendix IX by R.J. Motyka and C.J. Nye describes the chemistry of geothermal fluids. 78 refs., 16 figs., 3 tabs.

Nye, C.J.

1987-12-01T23:59:59.000Z

377

Utilization of scrap preheating and substitute slag conditioners for electric-arc-furnace steelmaking. Report of Investigations/1987  

SciTech Connect

The preheating of continuously fed, fragmented ferrous scrap charges by furnace offgases and the utilization of substitutes for imported fluorspar to condition electric steelmaking slags were investigated. Three types of continuous scrap-charging procedures were investigated to determine electrical energy consumption in a 1-st (short ton) electric arc furnace. Cold and preheated scrap charges were continuously fed at rates averaging 37.5 and 43.7 lb. min, respectively. The feed rate varied appreciably from test to test owing to hangup of the scrap in the charge bin. Approximately 7 pct less electrical energy was consumed in melting scrap preheated to 840 to 1,110 F by furnace offgases than in melting cold scrap. Overall energy consumptions were 888 kW per h/st for cold scrap, 829 kW per h/st for preheated scrap, and 637 kW per h/st for conventional backcharged scrap. Stack gases from scrap preheating averaged 120 F and a flow rate of 1,615 standard cubic feet per meter (scfm) compared with 220 F and 1,302 scfm for cold-charged scrap.

Elger, G.W.; Nafziger, R.H.; Tress, J.E.; Hartman, A.D.

1987-01-01T23:59:59.000Z

378

Oxidation Behavior of In-Flight Molten Aluminum Droplets in the Twin-Wire Electric Arc Thermal Spray Process  

Science Conference Proceedings (OSTI)

This paper examines the in-flight oxidation of molten aluminum sprayed in air using the twin-wire electric arc (TWEA) thermal spray process. The oxidation reaction of aluminum in air is highly exothermic and is represented by a heat generation term in the energy balance. Aerodynamic shear at the droplet surface enhances the amount of in-flight oxidation by: (1) promoting entrainment and mixing of the surface oxides within the droplet, and (2) causing a continuous heat generation effect that increases droplet temperature over that of a droplet without internal circulation. This continual source of heat input keeps the droplets in a liquid state during flight. A linear rate law based on the Mott-Cabrera theory was used to estimate the growth of the surface oxide layer formed during droplet flight. The calculated oxide volume fraction of an average droplet at impact agrees well with the experimentally determined oxide content for a typical TWEA-sprayed aluminum coating, which ranges from 3.3 to 12.7%. An explanation is provided for the elevated, nearly constant surface temperature (~ 2000 oC) of the droplets during flight to the substrate and shows that the majority of oxide content in the coating is produced during flight, rather than after deposition.

Donna Post Guillen; Brian G. Williams

2005-05-01T23:59:59.000Z

379

Developing a GIS-Based MCE Site Selection Tool in ArcGIS Using COM Technology IAJIT First Online Publication  

E-Print Network (OSTI)

Abstract: Site selection is a complex process for owners and analysts. This process involves not only technical requirements, but also economical, social, environmental and political demands that may result in conflicting objectives. Site selection is the process of finding locations that meet desired conditions set by the selection criteria. Geographic Information Systems (GIS) and Multi Criteria Evaluation techniques (MCE) are the two common tools employed to solve these problems. However, each suffers from serious shortcomings and could not be used alone to reach an optimum solution. This poses the challenge of integrating these tools. Developing and using GIS-based MCE tools for site selection is a complex process that needs well trained GIS developers and analysts who are not often available in most organizations. In this paper, a GIS-based Multicriteria Evaluation Site Selection Tool is developed in ArcGIS 9.3 using COM technology to achieve software interoperability. This tool can be used by engineers and planners with different levels of GIS and MCE knowledge to solve site selection problems. A typical case study is presented to demonstrate the application of the proposed tool..In addition, the paper presents a comprehensive discussion of the site selection process and characteristics.

Khalid Eldrandaly

2011-01-01T23:59:59.000Z

380

Cloud computing for dynamic systems  

Science Conference Proceedings (OSTI)

Cloud computing is a fast emerging model for enabling dynamic on-demand computing and IT-based services. It promotes dynamic properties and characteristics such as scalability, agility, flexibility, virtualised and distributed on-demand computing. However, ...

Khaled Sabry

2011-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Dynamic Scaling of Manipulator Trajectories  

E-Print Network (OSTI)

A fundamental time-scaling property of manipulator dynamics has been identified that allows modification of movement speed without complete dynamics recalculation. By exploiting this property, it can be determined ...

Hollerbach, John M.

1983-01-01T23:59:59.000Z

382

NETL: Energy System Dynamics Focus Area  

NLE Websites -- All DOE Office Websites (Extended Search)

Energy System Dynamics Onsite Research Energy System Dynamics Energy System Dynamics (ESD) is a focus area of the National Energy Technology Laboratory's Office of Research and...

383

Shared and Dynamic Libraries on Edison  

NLE Websites -- All DOE Office Websites (Extended Search)

Shared and Dynamic Libraries Shared and Dynamic Libraries The Edison system can support applications that use dynamic shared libraries (DSL) on the compute nodes. Some...

384

Dynamic Worldwide Solar Energy | Open Energy Information  

Open Energy Info (EERE)

Dynamic Worldwide Solar Energy Jump to: navigation, search Name Dynamic Worldwide Solar Energy Sector Solar Product US-based solar developer and financer. References Dynamic...

385

Next Generation Metallic Iron Nodule Technology in Electric Arc Steelmaking - Phase II  

Science Conference Proceedings (OSTI)

The current trend in the steel industry is a gradual decline in conventional steelmaking from taconite pellets in blast furnaces, and an increasing number of alternative processes using metallic scrap iron, pig iron and metallized iron ore products. Currently, iron ores from Minnesota and Michigan are pelletized and shipped to the lower Great Lakes ports as blast furnace feed. The existing transportation system and infrastructure is geared to handling these bulk materials. In order to expand the opportunities for the existing iron ore mines beyond their blast furnace customer base, a new material is needed to satisfy the needs of the emerging steel industry while utilizing the existing infrastructure and materials handling. A recent commercial installation employing Kobe Steel’s ITmk3 process, was installed in Northeastern Minnesota. The basic process uses a moving hearth furnace to directly reduce iron oxides to metallic iron from a mixture of iron ore, coals and additives. The resulting products can be shipped using the existing infrastructure for use in various steelmaking processes. The technology reportedly saves energy by 30% over the current integrated steelmaking process and reduces emissions by more than 40%. A similar large-scale pilot plant campaign is also currently in progress using JFE Steel’s Hi-QIP process in Japan. The objective of this proposal is to build upon and improve the technology demonstrated by Kobe Steel and JFE, by further reducing cost, improving quality and creating added incentive for commercial development. This project expands previous research conducted at the University of Minnesota Duluth’s Natural Resources Research Institute and that reported by Kobe and JFE Steel. Three major issues have been identified and are addressed in this project for producing high-quality nodular reduced iron (NRI) at low cost: (1) reduce the processing temperature, (2) control the furnace gas atmosphere over the NRI, and (3) effectively use sub-bituminous coal as a reductant. From over 4000 laboratory tube and box furnace tests, it was established that the correct combination of additives, fluxes, and reductant while controlling the concentration of CO and CO2 in the furnace atmosphere (a) lowers the operating temperature, (b) decreases the use of reductant coal (c) generates less micro nodules of iron, and (d) promotes desulphurization. The laboratory scale work was subsequently verified on 12.2 m (40 ft) long pilot scale furnace. High quality NRI could be produced on a routine basis using the pilot furnace facility with energy provided from oxy-gas or oxy-coal burner technologies. Specific strategies were developed to allow the use of sub-bituminous coals both as a hearth material and as part of the reaction mixture. Computational Fluid Dynamics (CFD) modeling was used to study the overall carbothermic reduction and smelting process. The movement of the furnace gas on a pilot hearth furnace and larger simulated furnaces and various means of controlling the gas atmosphere were evaluated. Various atmosphere control methods were identified and tested during the course of the investigation. Based on the results, the appropriate modifications to the furnace were made and tested at the pilot scale. A series of reduction and smelting tests were conducted to verify the utility of the processing conditions. During this phase, the overall energy use characteristics, raw materials, alternative fuels, and the overall economics predicted for full scale implementation were analyzed. The results indicate that it should be possible to lower reaction temperatures while simultaneously producing low sulfur, high carbon NRI if the right mix chemistry and atmosphere are employed. Recommendations for moving the technology to the next stage of commercialization are presented.

Donald R. Fosnacht; Iwao Iwasaki; Richard F. Kiesel; David J. Englund; David W. Hendrickson; Rodney L. Bleifuss

2010-12-22T23:59:59.000Z

386

Cell Dynamics and Process Control  

Science Conference Proceedings (OSTI)

ALUMINIUM REDUCTION TECHNOLOGY VII: Cell Dynamics And Process ... WITH RELEVANS TO POINT FEEDING ALUMINIUM CELL: Ove Kobbeltvedt, ...

387

Dynamic Behavior of Materials VI  

Science Conference Proceedings (OSTI)

Capturing Microstructural Features Related to Dynamic Damage Nucleation ... Structural Alumina during Low Velocity Impact Used in Protective Systems.

388

Interaction between economic dynamical systems  

Science Conference Proceedings (OSTI)

The paper considers economic dynamical systems, the state spaces being the Riemannian manifolds. Between two economic dynamical systems, global feedforward and the feedback interaction is defined and the connection between their linearization and prolongation ... Keywords: economic dynamical system, economic flow, feedback, feedforward, linearization, prolongation by derivation

Constantin Patrascoiu

2009-07-01T23:59:59.000Z

389

Accelerated Molecular Dynamics Methods  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamics Methods Dynamics Methods for Infrequent Events Arthur F. Voter Theoretical Division Los Alamos National Laboratory Los Alamos, New Mexico U.S. Department of Energy Theory Focus Session on Hydrogen Storage Materials Crystal City, VA May 18, 2006 Los Alamos Acknowledgments Blas P. Uberuaga (LANL, MST-8) Francesco Montalenti (U. Milano-Bicocca) Graeme Henkelman (U. Texas at Austin) Timothy C. Germann (LANL, X-7) James A. Sprague (NRL) Mads Sorensen (Novo Nordisk A/S, Copenhagen) Sriram Swaminarayan (LANL, MST-8) Steve Stuart (Clemson) David Sholl (Carnegie Mellon) John Hamilton (Sandia) Wolfgang Windl (Ohio State) Roger Smith (U. Loughborough) Robin Grimes (Imperial College) Kurt Sickafus (LANL, MST-8) Jacques Amar (U. Toledo) DOE Office of Basic Energy Sciences Motorola Intel Los Alamos Outline

390

Critical dynamics and decoherence  

SciTech Connect

We study dynamics of decoherence in a generic model where the environment is driven and undergoes a quantum phase transition. We model the environment by the Ising chain in the transverse field, and assume that the decohering system is a central spin-1/2. We found that when the environment is quenched slowly through the critical point, the decoherence factor of the central spin undergoes rapid decay that encodes the critical exponents of the environment. We also found that decoherence in a non-equilibrated, kink-contaminated, environment can be stronger than in a vacuum one. We derived a remarkably simple analytical expression that describes post-transition decoherence and predicts periodicities involving all system parameters. This research connects the fields of decoherence, quantum phase transitions, and Kibble-Zurek non-equilibrium dynamics.

Damski, Bogdan [Los Alamos National Laboratory; Quan, Haitao T [Los Alamos National Laboratory; Zurek, Wojciech H [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

391

Social Dynamics of Science  

E-Print Network (OSTI)

The birth and decline of disciplines are critical to science and society. However, no quantitative model to date allows us to validate competing theories of whether the emergence of scientific disciplines drives or follows the formation of social communities of scholars. Here we propose an agent-based model based on a \\emph{social dynamics of science,} in which the evolution of disciplines is guided mainly by the social interactions among scientists. We find that such a social theory can account for a number of stylized facts about the relationships between disciplines, authors, and publications. These results provide strong quantitative support for the key role of social interactions in shaping the dynamics of science. A "science of science" must gauge the role of exogenous events, such as scientific discoveries and technological advances, against this purely social baseline.

Sun, Xiaoling; Milojevi?, Staša; Flammini, Alessandro; Menczer, Filippo

2013-01-01T23:59:59.000Z

392

Dynamic radioactive particle source  

SciTech Connect

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

Moore, Murray E.; Gauss, Adam Benjamin; Justus, Alan Lawrence

2012-06-26T23:59:59.000Z

393

Meeting Residential Ventilation Standards Through Dynamic Control...  

NLE Websites -- All DOE Office Websites (Extended Search)

Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems Title Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation...

394

Contacts | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Points of Contact Science Points of Contact Name Research Area Doug Abernathy Wide Angular-Range Chopper Spectrometer (ARCS). Atomic-scale dynamics at thermal and epithermal energies Ke An Engineering Materials Diffractometer (VULCAN). Residual stress, deformation mechanism of materials, phase transitions/transformation, and in situ/operando neutron diffraction in material systems (e.g., working batteries). John Ankner Liquids Reflectometer (LR). Density profiles normal to the surface at liquid surfaces and liquid interfaces Bryan Chakoumakos Nuclear and magnetic crystal structure systematics and structure-property relationships among inorganic materials, powder and single-crystal neutron and x-ray diffraction methods Leighton Coates Macromolecular Neutron Diffractometer (MaNDi). Protein crystallography, biological structure and function

395

Development of an intelligent system for cooling rate and fill control in GMAW. [Gas Metal Arc Welding (GMAW)  

SciTech Connect

A control strategy for gas metal arc welding (GMAW) is developed in which the welding system detects certain existing conditions and adjusts the process in accordance to pre-specified rules. This strategy is used to control the reinforcement and weld bead centerline cooling rate during welding. Relationships between heat and mass transfer rates to the base metal and the required electrode speed and welding speed for specific open circuit voltages are taught to a artificial neural network. Control rules are programmed into a fuzzy logic system. TRADITOINAL CONTROL OF THE GMAW PROCESS is based on the use of explicit welding procedures detailing allowable parameter ranges on a pass by pass basis for a given weld. The present work is an exploration of a completely different approach to welding control. In this work the objectives are to produce welds having desired weld bead reinforcements while maintaining the weld bead centerline cooling rate at preselected values. The need for this specific control is related to fabrication requirements for specific types of pressure vessels. The control strategy involves measuring weld joint transverse cross-sectional area ahead of the welding torch and the weld bead centerline cooling rate behind the weld pool, both by means of video (2), calculating the required process parameters necessary to obtain the needed heat and mass transfer rates (in appropriate dimensions) by means of an artificial neural network, and controlling the heat transfer rate by means of a fuzzy logic controller (3). The result is a welding machine that senses the welding conditions and responds to those conditions on the basis of logical rules, as opposed to producing a weld based on a specific procedure.

Einerson, C.J.; Smartt, H.B.; Johnson, J.A.; Taylor, P.L. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Moore, K.L. (Idaho State Univ., Pocatello, ID (United States))

1992-01-01T23:59:59.000Z

396

Electrical properties of a-C:Mo films produced by dual-cathode filtered cathodic arc plasma deposition  

SciTech Connect

Molybdenum-containing amorphous carbon (a-C:Mo) thin films were prepared using a dual-cathode filtered cathodic arc plasma source with a molybdenum and a carbon (graphite) cathode. The Mo content in the films was controlled by varying the deposition pulse ratio of Mo and C. Film sheet resistance was measured in situ at process temperature, which was close to room temperature, as well as ex situ as a function of temperature (300-515 K) in ambient air. Film resistivity and electrical activation energy were derived for different Mo and C ratios and substrate bias. Film thickness was in the range 8-28 nm. Film resistivity varied from 3.55x10-4 Omega m to 2.27x10-6 Omega m when the Mo/C pulse ratio was increased from 0.05 to 0.4, with no substrate bias applied. With carbon-selective bias, the film resistivity was in the range of 4.59x10-2 and 4.05 Omega m at a Mo/C pulse ratio of 0.05. The electrical activation energy decreased from 3.80x10-2 to 3.36x10-4 eV when the Mo/C pulse ratio was increased in the absence of bias, and from 0.19 to 0.14 eV for carbon-selective bias conditions. The resistivity of the film shifts systematically with the amounts of Mo and upon application of substrate bias voltage. The intensity ratio of the Raman D-peak and G-peak (ID/IG) correlated with the pre-exponential factor (sigma 0) which included charge carrier density and density of states.

Sansongsiri, Sakon; Anders, Andre; Yodsombat, Banchob

2008-01-20T23:59:59.000Z

397

Definition: Dynamic Interchange Schedule Or Dynamic Schedule | Open Energy  

Open Energy Info (EERE)

Schedule Or Dynamic Schedule Schedule Or Dynamic Schedule Jump to: navigation, search Dictionary.png Dynamic Interchange Schedule Or Dynamic Schedule A telemetered reading or value that is updated in real time and used as a schedule in the AGC/ACE equation and the integrated value of which is treated as a schedule for interchange accounting purposes. Commonly used for scheduling jointly owned generation to or from another Balancing Authority Area.[1] Related Terms balancing authority, balancing authority area, smart grid References ↑ Glossary of Terms Used in Reliability Standards An in LikeLike UnlikeLike You like this.Sign Up to see what your friends like. line Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Dynamic_Interchange_Schedule_Or_Dynamic_Schedule&oldid=502492

398

Heat transfer dynamics  

Science Conference Proceedings (OSTI)

As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained.

Smith, T.M. (Marsden, Inc., Pennsauken, NJ (United States))

1994-08-01T23:59:59.000Z

399

Dynamic Chirality in Nuclei  

SciTech Connect

The possible chiral interpretation of twin bands in odd-odd nuclei was investigated in the Interacting Boson Fermion-Fermion Model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behaviour is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different beta and gamma fluctuations, induced by the exchange boson-fermion interaction of the Interacting Boson Fermion-Fermion Model. In both cases the chirality is weak and dynamic. The existence of doublets of bands in {sup 134}Pr can be attributed to dynamic chirality dominated by shape fluctuations.

Tonev, D. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Angelis, G. de [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Petkov, P. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); Ventura, A. [ENEA, 40129 Bologna and INFN, Sezione di Bologna (Italy)

2009-08-26T23:59:59.000Z

400

Gas-Phase Molecular Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Gas-Phase Molecular Dynamics Gas-Phase Molecular Dynamics The Gas-Phase Molecular Dynamics Group is dedicated to developing and applying spectroscopic and theoretical tools to challenging problems in chemical physics related to reactivity, structure, dynamics and kinetics of transient species. Recent theoretical work has included advances in exact variational solution of vibrational quantum dynamics, suitable for up to five atoms in systems where large amplitude motion or multiple strongly coupled modes make simpler approximations inadequate. Other theoretical work, illustrated below, applied direct dynamics, quantum force trajectory calculations to investigate a series of reactions of the HOCO radical. The potential energy surface for the OH + CO/ H + CO2 reaction, showing two barriers (TS1 and TS2) and the deep HOCO well along the minimum energy pathway. The inset figure shows the experimental and calculated reactivity of HOCO with selected collision partners. See J.S. Francisco, J.T. Muckerman and H.-G. Yu, "HOCO radical chemistry,"

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Particle Dynamics And Emergent Gravity  

E-Print Network (OSTI)

The emergent gravity proposal is examined within the framework of noncommutative QED/gravity correspondence from particle dynamics point of view.

Amir H. Fatollahi

2008-05-08T23:59:59.000Z

402

Nuclear Matter and Nuclear Dynamics  

E-Print Network (OSTI)

Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.

M Colonna

2009-02-26T23:59:59.000Z

403

Lubricants under high local pressure: Liquids act like solids  

E-Print Network (OSTI)

it is confined between two walls at large normal pressures. The atomic scale motion that occurs when the two, atomic- scale details of the plastic flow mechanism are investigated by means of molecular dynamics- city v over a broad velocity range. Under non-extreme condi- tions (intermediate pressures

Müser, Martin H.

404

EPID-based verification of the MLC performance for dynamic IMRT and VMAT  

Science Conference Proceedings (OSTI)

Purpose: In advanced radiotherapy treatments such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), verification of the performance of the multileaf collimator (MLC) is an essential part of the linac QA program. The purpose of this study is to use the existing measurement methods for geometric QA of the MLCs and extend them to more comprehensive evaluation techniques, and to develop dedicated robust algorithms to quantitatively investigate the MLC performance in a fast, accurate, and efficient manner. Methods: The behavior of leaves was investigated in the step-and-shoot mode by the analysis of integrated electronic portal imaging device (EPID) images acquired during picket fence tests at fixed gantry angles and arc delivery. The MLC was also studied in dynamic mode by the analysis of cine EPID images of a sliding gap pattern delivered in a variety of conditions including different leaf speeds, deliveries at fixed gantry angles or in arc mode, and changing the direction of leaf motion. The accuracy of the method was tested by detection of the intentionally inserted errors in the delivery patterns. Results: The algorithm developed for the picket fence analysis was able to find each individual leaf position, gap width, and leaf bank skewness in addition to the deviations from expected leaf positions with respect to the beam central axis with sub-pixel accuracy. For the three tested linacs over a period of 5 months, the maximum change in the gap width was 0.5 mm, the maximum deviation from the expected leaf positions was 0.1 mm and the MLC skewness was up to 0.2 Degree-Sign . The algorithm developed for the sliding gap analysis could determine the velocity and acceleration/deceleration of each individual leaf as well as the gap width. There was a slight decrease in the accuracy of leaf performance with increasing leaf speeds. The analysis results were presented through several graphs. The accuracy of the method was assessed as 0.01 mm for both the gap size and peak position determination. Conclusions: This study provides fast, easy, and accurate test methods for routine QA of the MLC performance and helps in faster troubleshooting of MLC problems in both IMRT and VMAT treatments.

Rowshanfarzad, Pejman; Sabet, Mahsheed; Barnes, Michael P.; O'Connor, Daryl J.; Greer, Peter B. [School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW 2308 (Australia); Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, NSW 2310 (Australia); School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW 2308 (Australia); Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, NSW 2310, Australia and School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, NSW 2308 (Australia)

2012-10-15T23:59:59.000Z

405

Subduction dynamics at the middle America trench : new constraints from swath bathymetry, multichannel seismic data, and ¹?Be  

E-Print Network (OSTI)

The cosmogenic radionuclide ¹?Be is a unique tracer of shallow sediment subduction in volcanic arcs. The range in ¹?Be enrichment in the Central American Volcanic Arc between Guatemala and Costa Rica is not controlled by ...

Kelly, Robyn K

2003-01-01T23:59:59.000Z

406

and Industry Dynamics  

E-Print Network (OSTI)

We assess the long-run dynamic implications of market-based regulation of carbon dioxide emissions in the US Portland cement industry. We consider several alternative policy designs, including mechanisms that use production subsidies to partially offset compliance costs and border tax adjustments to penalize emissions associated with foreign imports. Our results highlight two general countervailing market distortions. First, following Buchanan (1969), reductions in product market surplus and allocative inefficiencies due to market power in the domestic cement market counteract the social benefits of carbon abatement. Second, tradeexposure to unregulated foreign competitors leads to emissions “leakage ” which offsets domestic emissions reductions. Taken together, these forces result in social welfare losses under policy regimes that fully internalize the emissions externality. In contrast, market-based policies that incorporate design features to mitigate the exercise of market power and emissions leakage can deliver welfare gains. 1

Meredith Fowlie; Mar Reguant; Stephen P. Ryan; Meredith Fowlie; Mar Reguant; Stephen P. Ryan

2013-01-01T23:59:59.000Z

407

Dynamic Radiographic Imaging  

Science Conference Proceedings (OSTI)

A radiographic system recently developed by American and Russian collaborators is designed to capture multiple images of a dynamic event lasting less than 10 microseconds. Various optical and electro-optical components were considered and their performance compared. The final system employed a solid crystal of lutetium oxyorthosilicate doped with cerium (LSO:Ce or LSO) for X-ray-to-light conversion with a coherent fiber optic bundle to relay the scintillator image to a streak camera with charge coupled device (CCD) readout. Resolution and sensitivity studies were carried out for this system on two different sources of X-rays: a 20 MeV microtron and a 70 MeV betatron.

Volkov, A.; Turley, D.; Veeser, L.; Lukyanov, N.; Yegorov, N.; Baker, S.A.; Mirenko, V.; Lewis, W.; Kuropatkin, Y.

1999-06-01T23:59:59.000Z

408

ARC4461kit  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

talk about a Disaster Supplies Kit? talk about a Disaster Supplies Kit? After a disaster, local officials and relief workers will be on the scene, but they cannot reach everyone immediately. You could get help in hours, or it may take days. Basic services, such as electricity, gas, water, and tele- phones, may be cut off, or you may have to evacuate at a moment's notice. You probably won't have time to shop or search for the supplies you'll need. Your family will cope best by preparing for disaster before it strikes. What is a Disaster Supplies Kit? Assembling the supplies you might need following a disaster is an impor- tant part of your Family Disaster Plan. Following a disaster, having extra sup- plies at home or supplies to take with you in the event of an evacuation can help your family endure evacuation

409

Arc Position Sensing  

NLE Websites -- All DOE Office Websites (Extended Search)

control methods that will permit VAR to produce consistent defect-free ingots. Patent Details U.S. patent number 8,111,059; issued 272012; titled "Electric Current...

410

ARC Approved By:  

E-Print Network (OSTI)

the consistency and quality of the study results through a comprehensive review and advisory process and concur with the results herein.

Enceladus $b Mission; Kim Reh; John Elliott; Tom Spilker; Kim Reh; Gentry Lee

2007-01-01T23:59:59.000Z

411

Dynamic Vnodes - design and implementation  

Science Conference Proceedings (OSTI)

Dynamic vnodes make the UNIX kernel responsive to a varying demand for vnodes, without a need to rebuild the kernel. It also optimizes the usage of memory by deallocating excess vnodes. This paper describes the design and implementation of dynamic vnodes ...

Aju John

1995-01-01T23:59:59.000Z

412

Dynamic model for hydraulic dissipators  

Science Conference Proceedings (OSTI)

The authors propose a mathematical model of a hydraulic link with energy dissipation, the device working reversibly to the alternative traction and compression movement. The dynamic behavior of the energy hydraulic dissipater depends on the instantaneous ... Keywords: dissipater's control, dynamic behavior, hydraulic dissipater, mathematical model

Adrian S. Axinti; Gavril Axinti

2009-03-01T23:59:59.000Z

413

Fluctuations in molecular dynamics simulations  

Science Conference Proceedings (OSTI)

Statistical fluctuations of a system about its equilibrium state, monitored in a molecular dynamics simulation, are an effective means of computing the thermodynamic and kinetic properties of interfaces in metals and alloys. In this work, three applications ... Keywords: Fluctuations, Grain boundaries, Interfaces, Interfacial free energy, Mobility, Molecular dynamics

J. J. Hoyt; Z. T. Trautt; M. Upmanyu

2010-03-01T23:59:59.000Z

414

Dynamic spectrum management using GA  

Science Conference Proceedings (OSTI)

Thousands of equipments of the wireless network and the mobile devices are widely used and the demand of dynamic spectrum resources is significantly growing. How to maximize the social utility in modern technique becomes an important issue. In this paper, ... Keywords: Shannon utility, background interference, crosstalk, dynamic spectrum management, genetic algorithm

Ping-Liang Chen; Chia-Liang Peng; Shin-Jia Chen; Yu-Cheng Lin

2011-12-01T23:59:59.000Z

415

Periodicity estimation of Dynamic Textures  

Science Conference Proceedings (OSTI)

Dynamic Textures (DTs) are image sequences of natural events like fire, smoke, water etc., that possesses regular motion patterns. Periodicity is a widely used tool to analyse regular structures of periodic one dimensional signals as well as two dimensional ... Keywords: co-occurrence matrix, dynamic textures, image sequences, image texture analysis, motion patterns, natural events, periodicity estimation, temporal textures

Khalid Zaman Bijon; Ahmed Hasan; Ashfaqur Rahman; Manzur Murshed

2008-03-01T23:59:59.000Z

416

An investigation of temporal regularization techniques for dynamic PET reconstructions using temporal splines  

SciTech Connect

The use of a temporal B-spline basis for the reconstruction of dynamic positron emission tomography data was investigated. Maximum likelihood (ML) reconstructions using an expectation maximization framework and maximum A-posteriori (MAP) reconstructions using the generalized expectation maximization framework were evaluated. Different parameters of the B-spline basis of such as order, number of basis functions and knot placing were investigated in a reconstruction task using simulated dynamic list-mode data. We found that a higher order basis reduced both the bias and variance. Using a higher number of basis functions in the modeling of the time activity curves (TACs) allowed the algorithm to model faster changes of the TACs, however, the TACs became noisier. We have compared ML, Gaussian postsmoothed ML and MAP reconstructions. The noise level in the ML reconstructions was controlled by varying the number of basis functions. The MAP algorithm penalized the integrated squared curvature of the reconstructed TAC. The postsmoothed ML was always outperformed in terms of bias and variance properties by the MAP and ML reconstructions. A simple adaptive knot placing strategy was also developed and evaluated. It is based on an arc length redistribution scheme during the reconstruction. The free knot reconstruction allowed a more accurate reconstruction while reducing the noise level especially for fast changing TACs such as blood input functions. Limiting the number of temporal basis functions combined with the adaptive knot placing strategy is in this case advantageous for regularization purposes when compared to the other regularization techniques.

Verhaeghe, Jeroen; D'Asseler, Yves; Vandenberghe, Stefaan; Staelens, Steven; Lemahieu, Ignace [Department of Electronics and Information Systems, Medical Image and Signal Processing Group, Ghent University, Ghent, 9000 (Belgium)

2007-05-15T23:59:59.000Z

417

The effects of cyclic and dynamic loading on the fracture resistance of nuclear piping steels. Technical report, October 1992--April 1996  

SciTech Connect

This report presents the results of the material property evaluation efforts performed within Task 3 of the IPIRG-2 Program. Several related investigations were conducted. (1) Quasi-static, cyclic-load compact tension specimen experiments were conducted using parameters similar to those used in IPIRG-1 experiments on 6-inch nominal diameter through-wall-cracked pipes. These experiments were conducted on a TP304 base metal, an A106 Grade B base metal, and their respective submerged-arc welds. The results showed that when using a constant cyclic displacement increment, the compact tension experiments could predict the through-wall-cracked pipe crack initiation toughness, but a different control procedure is needed to reproduce the pipe cyclic crack growth in the compact tension tests. (2) Analyses conducted showed that for 6-inch diameter pipe, the quasi-static, monotonic J-R curve can be used in making cyclic pipe moment predictions; however, sensitivity analyses suggest that the maximum moments decrease slightly from cyclic toughness degradation as the pipe diameter increases. (3) Dynamic stress-strain and compact tension tests were conducted to expand on the existing dynamic database. Results from dynamic moment predictions suggest that the dynamic compact tension J-R and the quasi-static stress-strain curves are the appropriate material properties to use in making dynamic pipe moment predictions.

Rudland, D.L.; Brust, F.; Wilkowski, G.M.

1996-12-01T23:59:59.000Z

418

A Generic Dynamic Emulator  

E-Print Network (OSTI)

In applied sciences, we often deal with deterministic simulation models that are too slow for simulation-intensive tasks such as calibration or real-time control. In this paper, an emulator for a generic dynamic model, given by a system of ordinary non-linear differential equations, is developed. The non-linear differential equations are linearized and Gaussian white noise is added to account for the non-linearities. The resulting linear stochastic system is conditioned on a set of solutions of the non-linear equations that have been calculated prior to the emulation. A path-integral approach is used to derive the Gaussian distribution of the emulated solution. The solution reveals that most of the computational burden can be shifted to the conditioning phase of the emulator and the complexity of the actual emulation step only scales like $\\mathcal O(Nnm^2)$, where $N$ is the number of time-points at which the solution is to be emulated, $n$ the number of solutions the emulator is conditioned on and $m$ the n...

Albert, Carlo

2011-01-01T23:59:59.000Z

419

Dynamic Fault Detection Chassis  

Science Conference Proceedings (OSTI)

Abstract The high frequency switching megawatt-class High Voltage Converter Modulator (HVCM) developed by Los Alamos National Laboratory for the Oak Ridge National Laboratory's Spallation Neutron Source (SNS) is now in operation. One of the major problems with the modulator systems is shoot-thru conditions that can occur in a IGBTs H-bridge topology resulting in large fault currents and device failure in a few microseconds. The Dynamic Fault Detection Chassis (DFDC) is a fault monitoring system; it monitors transformer flux saturation using a window comparator and dV/dt events on the cathode voltage caused by any abnormality such as capacitor breakdown, transformer primary turns shorts, or dielectric breakdown between the transformer primary and secondary. If faults are detected, the DFDC will inhibit the IGBT gate drives and shut the system down, significantly reducing the possibility of a shoot-thru condition or other equipment damaging events. In this paper, we will present system integration considerations, performance characteristics of the DFDC, and discuss its ability to significantly reduce costly down time for the entire facility.

Mize, Jeffery J [ORNL

2007-01-01T23:59:59.000Z

420

ICFA Beam Dynamics Newsletter  

SciTech Connect

The Collider-Accelerator Department at Brookhaven National Laboratory is building a high-brightness 500 mA capable Energy Recovery Linac (ERL) as one of its main R&D thrusts towards eRHIC, the polarized electron - hadron collider as an upgrade of the operating RHIC facility. The ERL is in final assembly stages, with injection commisioning starting in October 2012. The objective of this ERL is to serve as a platform for R&D into high current ERL, in particular issues of halo generation and control, Higher-Order Mode (HOM) issues, coherent emissions for the beam and high-brightness, high-power beam generation and preservation. The R&D ERL features a superconducting laser-photocathode RF gun with a high quantum efficiency photoccathode served with a load-lock cathode delivery system, a highly damped 5-cell accelerating cavity, a highly flexible single-pass loop and a comprehensive system of beam instrumentation. In this ICFA Beam Dynamics Newsletter article we will describe the ERL in a degree of detail that is not usually found in regular publications. We will discuss the various systems of the ERL, following the electrons from the photocathode to the beam dump, cover the control system, machine protection etc and summarize with the status of the ERL systems.

Ben-Zvi I.; Kuczewski A.; Altinbas, Z.; Beavis, D.; Belomestnykh,; Dai, J. et al

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Fermionic Molecular Dynamics for nuclear dynamics and thermodynamics  

E-Print Network (OSTI)

A new Fermionic Molecular Dynamics (FMD) model based on a Skyrme functional is proposed in this paper. After introducing the basic formalism, some first applications to nuclear structure and nuclear thermodynamics are presented

K. H. O. Hasnaoui; Ph. Chomaz; F. Gulminelli

2008-12-02T23:59:59.000Z

422

Complex Crystallization Dynamics in Amorphous Germanium ...  

Science Conference Proceedings (OSTI)

We used dynamic transmission electron microscopy [2] to study in situ this fast dynamics ... of Magnetism in Multiferroic Heterostructures and Low-power Devices ...

423

16.07 Dynamics, Fall 2004  

E-Print Network (OSTI)

Dynamics starts with fundamentals of Newtonian mechanics. Further topics include kinematics, particle dynamics, motion relative to accelerated reference frames, work and energy, impulse and momentum, systems of particles ...

Peraire, Jaume

424

Molecular dynamics simulations and drug discovery  

E-Print Network (OSTI)

JE: On the determination of molecular fields. II. From thescalability for parallel molecular dynamics. J Comput PhysKale L, Schulten K: Scalable molecular dynamics with NAMD. J

Durrant, Jacob D; McCammon, J Andrew

2011-01-01T23:59:59.000Z

425

Dynamic stall on wind turbine blades  

DOE Green Energy (OSTI)

Dynamic loads must be predicted accurately in order to estimate the fatigue life of wind turbines operating in turbulent environments. Dynamic stall contributes to increased dynamic loads during normal operation of all types of horizontal-axis wind turbine (HAWTs). This report illustrates how dynamic stall varies throughout the blade span of a 10 m HAWT during yawed and unyawed operating conditions. Lift, drag, and pitching moment coefficients during dynamics stall are discussed. Resulting dynamic loads are presented, and the effects of dynamic stall on yaw loads are demonstrated using a yaw loads dynamic analysis (YAWDYN). 12 refs., 22 figs., 1 tab.

Butterfield, C.P.; Simms, D.; Scott, G. [National Renewable Energy Lab., Golden, CO (United States)] [National Renewable Energy Lab., Golden, CO (United States); Hansen, A.C. [Utah Univ., Salt Lake City, UT (United States)] [Utah Univ., Salt Lake City, UT (United States)

1991-12-01T23:59:59.000Z

426

The power of dynamic pricing  

SciTech Connect

Using data from a generic California utility, it can be shown that it is feasible to develop dynamic pricing rates for all customer classes. These rates have the potential to reduce system peak demands from 1 to 9 percent. (author)

Faruqui, Ahmad; Hledik, Ryan; Tsoukalis, John

2009-04-15T23:59:59.000Z

427

Dynamical Predictability of Monthly Means  

Science Conference Proceedings (OSTI)

We have attempted to determine the theoretical upper limit of dynamical predictability of monthly means for prescribed nonfluctuating external forcings. We have extended the concept of “classical” predictability, which primarily refers to the ...

J. Shukla

1981-12-01T23:59:59.000Z

428

LANL | Physics | Dynamic Plutonium Experiments  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic plutonium experiments Dynamic plutonium experiments Since the end of nuclear testing the nation has had to rely on sophisticated computer models to ensure the safety and reliability of the nuclear weapons stockpile. This program is known as science-based stockpile stewardship. Despite possessing the world's fastest computers and most advanced modeling capability, the behavior of materials under dynamic loads that occur in a nuclear weapon are difficult to accurately model. The Dynamic Plutonium experimental program carries out experiments at the Nevada National Security Site on plutonium driven by high explosives. These experiments are needed to measure and understand the behavior of plutonium under extreme conditions. Physics Division has unique capabilities in high-speed x-ray imaging and velocimetry (measuring the

429

Stochastic Dynamics of Baroclinic Waves  

Science Conference Proceedings (OSTI)

The maintenance of variance and attendant heat flux in linear, forced, dissipative baroclinic shear flows subject to stochastic excitation is examined. The baroclinic problem is intrinsically nonnormal and its stochastic dynamics is found to ...

Brian F. Farrell; Petros J. Ioannou

1993-12-01T23:59:59.000Z

430

Essays on dynamic sales mechanisms  

E-Print Network (OSTI)

This thesis is a collection of three essays on dynamic sales mechanisms. The first chapter analyzes the Name Your Own Price (NYOP) mechanism adopted by Priceline.com. Priceline.com, a website helping travelers obtain ...

Chen, Chia-Hui, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

431

Dynamical Processes of Block Evolution  

Science Conference Proceedings (OSTI)

The dynamical processes associated with block evolution are investigated by analyzing a GCM run, forced with perpetual January conditions. The core of the analysis lies on the temporal evolution of the blocks and on vorticity budget terms ...

Benjamin A. Cash; Sukyoung Lee

2000-10-01T23:59:59.000Z

432

Ensemble Dynamics and Bred Vectors  

Science Conference Proceedings (OSTI)

The new concept of an ensemble bred vector (EBV) algorithm is introduced to assess the sensitivity of model outputs to changes in initial conditions for weather forecasting. The new algorithm is based on collective dynamics in essential ways. As ...

Nusret Balci; Anna L. Mazzucato; Juan M. Restrepo; George R. Sell

2012-07-01T23:59:59.000Z

433

Dynamic Pricing: A learning Approach  

E-Print Network (OSTI)

We present an optimization approach for jointly learning the demand as a functionof price, and dynamically setting prices of products in an oligopoly environment in order to maximize expected revenue. The models we consider ...

Bertsimas, Dimitris J.

434

Dynamic Mercury Cycling Model Upgrade  

Science Conference Proceedings (OSTI)

This technical update describes the status of activities to upgrade the Dynamic Mercury Cycling Model (D-MCM), an EPRI simulation model that predicts mercury cycling and bioaccumulation in lakes.

2008-12-17T23:59:59.000Z

435

Adding dynamic types to C  

Science Conference Proceedings (OSTI)

Developers using statically typed languages such as C? and Java are increasingly having to interoperate with APIs and object models defined in dynamic languages. This impedance mismatch results in code that is difficult to understand, awkward to ...

Gavin Bierman; Erik Meijer; Mads Torgersen

2010-06-01T23:59:59.000Z

436

Dynamic Graphics Using Quasi Parallelism  

E-Print Network (OSTI)

Dynamic computer graphics is best represented as several processes operating in parallel. Full parallel processing, however, entails much complex mechanism making it difficult to write simple, intuitive programs for ...

Kahn, Kenneth M.

1978-06-01T23:59:59.000Z

437

Theoretical Experiments on Cumulus Dynamics  

Science Conference Proceedings (OSTI)

The sensitivity of a two-dimensional cloud model to changes in microphysical characteristics was examined using two soundings. The dynamical evolution of clouds having relatively warm bases was controlled more by rapidity of the production of ...

L. Randall Koenig; Francis W. Murray

1983-05-01T23:59:59.000Z

438

Quasigeostrophic Dynamics of the Tropopause  

Science Conference Proceedings (OSTI)

The dynamical properties of potential temperature anomalies on the tropopause are analyzed for quasigeo-strophic flow on an f plane. The potential vorticity is taken to he piecewise constant, with a single discontinuity at the tropopause. The ...

Martin Juckes

1994-10-01T23:59:59.000Z

439

THz Dynamic Nuclear Polarization NMR  

E-Print Network (OSTI)

Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) spectroscopy by using high frequency microwaves to transfer the polarization of the electrons to the nuclear spins. The ...

Nanni, Emilio Alessandro

440

EPRI Power System Dynamics Tutorial  

Science Conference Proceedings (OSTI)

Operation of today's increasingly complex power systems requires comprehensive training of system operators and operations engineers. By increasing their awareness and understanding of dynamic phenomena, the EPRI Power System Dynamics Tutorial can improve an operator's ability to take effective actioneither preventive or corrective. This latest version of the tutorial represents an update of key topics to reflect industry restructuring under the vision of the Federal Energy Regulatory Commission (FERC) a...

2009-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Development of a novel quality assurance system based on rolled-up and rolled-out radiochromic films in volumetric modulated arc therapy  

Science Conference Proceedings (OSTI)

Purpose: To develop a cylindrical phantom with rolled-up radiochromic films and dose analysis software in the rolled-out plane for quality assurance (QA) in volumetric modulated arc therapy (VMAT). Methods: The phantom consists of an acrylic cylindrical body wrapped with radiochromic film inserted into an outer cylindrical shell of 5 cm thickness. The rolled-up films with high spatial resolution enable detection of specific dose errors along the arc trajectory of continuously irradiated and modulated beams in VMAT. The developed dose analysis software facilitates dosimetric evaluation in the rolled-up and rolled-out planes of the film; the calculated doses on the corresponding points where the rolled-up film was placed were reconstructed into a rectangular dose matrix equivalent to that of the rolled-out plane of the film. The VMAT QA system was implemented in 3 clinical cases of prostate, nasopharynx, and pelvic metastasis. Each calculated dose on the rolled-out plane was compared with measurement values by modified gamma evaluation. Detected positions of dose disagreement on the rolled-out plane were also distinguished in cylindrical coordinates. The frequency of error occurrence and error distribution were summarized in a histogram and in an axial view of rolled-up plane to intuitively identify the corresponding positions of detected errors according to the gantry angle. Results: The dose matrix reconstructed from the developed VMAT QA system was used to verify the measured dose distribution along the arc trajectory. Dose discrepancies were detected on the rolled-out plane and visualized on the calculated dose matrix in cylindrical coordinates. The error histogram obtained by gamma evaluation enabled identification of the specific error frequency at each gantry angular position. The total dose error occurring on the cylindrical surface was in the range of 5%-8% for the 3 cases. Conclusions: The developed system provides a practical and reliable QA method to detect dosimetric errors according to the gantry angle. Film dosimetry based on rolled-up and rolled-out techniques leads to dose verification in the subspaces of the 3D dose volume. The system can be employed as an alternative tool to detect the pitfalls of planar dose verification.

Park, Ji-Yeon; Lee, Jeong-Woo; Choi, Kyoung-Sik; Lee, Jung Seok; Kim, You-Hyun; Hong, Semie; Suh, Tae-Suk [Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Research Institute of Health Science, College of Health Science, Korea University, Seoul 136-703 (Korea, Republic of) and Department of Radiation Oncology, Konkuk University Medical Center, Seoul 143-729 (Korea, Republic of); Department of Radiation Oncology, Anyang SAM Hospital, Anyang 430-733 (Korea, Republic of) and Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Department of Radiation Oncology, Anyang SAM Hospital, Anyang 430-733 (Korea, Republic of); Department of Radiologic Science, College of Health Science, Korea University, Seoul 136-703 (Korea, Republic of); Department of Radiation Oncology, Konkuk University Medical Center, Seoul 143-729 (Korea, Republic of); Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of)

2011-12-15T23:59:59.000Z

442

Dynamic modeling of power systems  

Science Conference Proceedings (OSTI)

Morgantown Energy Technology Center`s (METC) Process and Project Engineering (P&PE) personnel continue to refine and modify dynamic modeling or simulations for advanced power systems. P&PE, supported by Gilbert/Commonwealth, Inc. (G/C), has adapted PC/TRAX commercial dynamic software to include equipment found in advanced power systems. PC/TRAX`s software contains the equations that describe the operation of standard power plant equipment such as gas turbines, feedwater pumps, and steam turbines. The METC team has incorporated customized dynamic models using Advanced Continuous Simulation Language (ACSL) code for pressurized circulating fluidized-bed combustors, carbonizers, and other components that are found in Advanced Pressurized Fluidized-Bed Combustion (APFBC) systems. A dynamic model of a commercial-size APFBC power plant was constructed in order to determine representative operating characteristics of the plant and to gain some insight into the best type of control system design. The dynamic model contains both process and control model components. This presentation covers development of a model used to describe the commercial APFBC power plant. Results of exercising the model to simulate plant performance are described and illustrated. Information gained during the APFBC study was applied to a dynamic model of a 1-1/2 generation PFBC system. Some initial results from this study are also presented.

Reed, M.; White, J.

1995-12-01T23:59:59.000Z

443

HAWT performance with dynamic stall  

DOE Green Energy (OSTI)

In this report we calculated the effects of flow nonuniformities (wing shear, tower wake, yaw, and large-scale turbulence) on the performance of a horizontal axis wind turbine, accounting for dynamic stall. We modified the PROP program to incorporate and compare these effects with the uniform flow case. The MIT model, which predicts dynamic lift coefficients substantially higher than the static maximum values and includes a crude model of the vortex roll-off phenomenon, represented dynamic stall. As associated model for drag was also used. The dynamic stall model was tested against experimental data for three typical reduced frequencies. Good instantaneous correlation was obtained. The effects of nonuniformities with and without the dynamic stall were calculated using the Westinghouse Mod O and Enertech 44/25 turbines. Modeling the dynamic stall has little effect on performance. Furthermore, the performance with nonuniform flow differed only slightly from the uniform flow case. Thus the now PROP model provides a powerful general capability to handle nonuniform flows.

Hibbs, B.D.

1986-02-01T23:59:59.000Z

444

Simulations of electron-cloud heat load for the cold arcs of the CERN Large Hadron Collider and its high-luminosity upgrade scenarios  

E-Print Network (OSTI)

The heat load generated by an electron cloud in the cold arcs of the Large Hadron Collider (LHC) is a concern for operation near and beyond nominal beam current. We report the results of simulation studies, with updated secondary- emission models, which examine the severity of the electron heat load over a range of possible operation parameters, both for the nominal LHC and for various luminosity-upgrade scenarios, such as the so-called ‘‘full crab crossing’’ and ‘‘early separation’’ schemes, the ‘‘large Piwinski angle’’ scheme, and a variant of the latter providing ‘‘compatibility’’ with the (upgraded) LHCb experiment. The variable parameters considered are the maximum secondary-emission yield, the number of particles per bunch, and the spacing between bunches. In addition, the dependence of the heat load on the longitudinal bunch profile is investigated.

Maury Cuna, H; Zimmermann, F

2012-01-01T23:59:59.000Z

445

MeV-ion beam analysis of the interface between filtered cathodic arc-deposited a-carbon and single crystalline silicon  

SciTech Connect

Amorphous carbon (a-C) films were deposited on Si(100) wafers by a filtered cathodicvacuum arc (FCVA) plasma source. A negative electrical bias was applied tothe silicon substrate in order to control the incident energy of carbon ions. Effects ofthe electrical bias on the a-C/Si interface characteristics were investigated by usingstandard Rutherford backscattering spectrometry (RBS) in the channeling modewith 2.1-MeV He2+ ions. The shape of the Si surface peaks of the RBS/channelingspectra reflects the degree of interface disorder due to atomic displacement fromthe bulk position of the Si crystal. Details of the analysis method developed aredescribed. It was found that the width of the a-C/Si interface increases linearlywith the substrate bias voltage but not the thickness of the a-C film.

Kamwanna, T.; Pasaja, N.; Yu, L.D.; Vilaithong, T.; Anders, A.; Singkarat, S.

2008-08-01T23:59:59.000Z

446

Projected dynamical systems in a complementarity formalism  

Science Conference Proceedings (OSTI)

Projected dynamical systems have been introduced by Dupuis and Nagurney as dynamic extensions of variational inequalities. In the systems and control literature, complementarity systems have been studied as input/output dynamical systems whose inputs ... Keywords: Complementarity, Discontinuous dynamical systems, Optimization, Systems theory, Variational inequalities

W. P. M. H. Heemels; J. M. Schumacher; S. Weiland

2000-09-01T23:59:59.000Z

447

Investigation of the thermal regime and geologic history of the Cascade volcanic arc: First phase of a program for scientific drilling in the Cascade Range  

DOE Green Energy (OSTI)

A phased, multihole drilling program with associated science is proposed as a means of furthering our understanding of the thermal regime and geologic history of the Cascade Range of Washington, Oregon, and northern California. The information obtained from drilling and ancillary geological and geophysical investigations will contribute to our knowledge in the following general areas: (1) the magnitude of the regional background heat flow of parts of the Quaternary volcanic belt dominated by the most abundant volcanic rock types, basalt and basaltic andesite; (2) the nature of the heat source responsible for the regional heat-flow anomaly; (3) the characteristics of the regional hydrothermal and cold-water circulation; the rates of volcanism for comparison with models for the rate and direction of plate convergence of the Cascades; (5) the history of deformation and volcanism in the volcanic arc that can be related to subduction; (6) the present-day stress regime of the volcanic arc and the relation of these stresses to plate interactions and possible large earthquakes; and the current geometry of the subducted oceanic plate below the Cascade Range and the relationship of the plate to the distribution of heat flow, Quaternary volcanism, and Quaternary deformation. Phase I research will be directed toward a detailed investigation of the Santiam Pass segment. In concert with the Santiam Pass research, a detailed study of the nearby Breitenbush Hot Springs area is also recommended as a component of Phase I. The object of the Breitenbush research is to study one of the hottest known Cascade hydrothermal systems, which coincidentally also has a good geological and geophysical data base. A coordinated program of drilling, sampling, subsurface measurements, and surface surveys will be associated with the drilling of several holes.

Priest, G.R.

1987-01-01T23:59:59.000Z

448

Simple Dynamic Gasifier Model That Runs in Aspen Dynamics  

SciTech Connect

Gasification (or partial oxidation) is a vital component of 'clean coal' technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel for driving combustion turbines. Gasification units in a chemical plant generate gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids. So steady-state design and optimization studies of processes with gasifiers can be undertaken. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way.

Robinson, P.J.; Luyben, W.L. [Lehigh University, Bethlehem, PA (United States). Dept. of Chemical Engineering

2008-10-15T23:59:59.000Z

449

DYNAMIC SCREENING IN SOLAR PLASMA  

Science Conference Proceedings (OSTI)

In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions has been revisited. In particular, the issue of dynamic effects has been raised by Shaviv and Shaviv who apply the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean field assumption inherent in Salpeter's approximation. In this paper, we reproduce their numerical analysis of the screening energy in the plasma of the solar core and conclude that the effects of dynamic screening are relevant and should be included when stellar nuclear reaction rates are computed.

Mao, Dan; Daeppen, Werner [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089 (United States); Mussack, Katie [Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom)], E-mail: mussack@ast.cam.ac.uk

2009-08-20T23:59:59.000Z

450

Nonlinear Fluid Dynamics from Gravity  

E-Print Network (OSTI)

Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields -- arbitrary functions of the coordinates on the boundary of AdS5 -- we use Einstein's equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.

Sayantani Bhattacharyya; Veronika E Hubeny; Shiraz Minwalla; Mukund Rangamani

2007-12-14T23:59:59.000Z

451

Ab-Initio Molecular Dynamics  

E-Print Network (OSTI)

Computer simulations and molecular dynamics in particular, is a very powerful method to provide detailed and essentially exact informations of classical many-body problems. With the advent of \\textit{ab-initio} molecular dynamics, where the forces are computed on-the-fly by accurate electronic structure calculations, the scope of either method has been greatly extended. This new approach, which unifies Newton's and Schr\\"odinger's equations, allows for complex simulations without relying on any adjustable parameter. This review is intended to outline the basic principles as well as a survey of the field. Beginning with the derivation of Born-Oppenheimer molecular dynamics, the Car-Parrinello method as well as novel hybrid scheme that unifies best of either approach are discussed. The predictive power is demonstrated by a series of applications ranging from insulators to semiconductors and even metals in condensed phases.

Kühne, Thomas D

2012-01-01T23:59:59.000Z

452

Dynamic screening in solar plasma  

E-Print Network (OSTI)

In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions has been revisited. In particular the issue of dynamic effects has been raised by Shaviv and Shaviv who apply the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean-field assumption inherent in Salpeter's approximation. In this paper we reproduce their numerical analysis of the screening energy in the plasma of the solar core and conclude that the effects of dynamic screening are relevant and should be included when stellar nuclear reaction rates are computed.

Mao, Dan; Däppen, Werner

2009-01-01T23:59:59.000Z

453

A multipulsed dynamic moire interferometer  

DOE Patents (OSTI)

An improved dynamic moire interferometer is described that is comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event. 5 figs.

Deason, V.A.

1989-06-10T23:59:59.000Z

454

Fairness and dynamic pricing: comments  

Science Conference Proceedings (OSTI)

In ''The Ethics of Dynamic Pricing,'' Ahmad Faruqui lays out a case for improved efficiency in using dynamic prices for retail electricity tariffs and addresses various issues about the distributional effects of alternative pricing mechanisms. The principal contrast is between flat or nearly constant energy prices and time-varying prices that reflect more closely the marginal costs of energy and capacity. The related issues of fairness criteria, contracts, risk allocation, cost allocation, means testing, real-time pricing, and ethical policies of electricity market design also must be considered. (author)

Hogan, William W.

2010-07-15T23:59:59.000Z

455

Nonlinear manifold learning for dynamic shape and dynamic appearance  

Science Conference Proceedings (OSTI)

Our objective is to learn representations for the shape and the appearance of moving (dynamic) objects that support tasks such as synthesis, pose recovery, reconstruction, and tracking. In this paper, we introduce a framework that aims to learn landmark-free ... Keywords: Appearance-based vision, Gait analysis, Human motion analysis, Manifold learning, Motion analysis, Shape analysis

Ahmed Elgammal; Chan-Su Lee

2007-04-01T23:59:59.000Z

456

Dynamic Scheduling via Polymatroid Optimization  

Science Conference Proceedings (OSTI)

Dynamic scheduling of multi-class jobs in queueing systems has wide ranging applications, but in general is a very difficult control problem. Here we focus on a class of systems for which conservation laws hold. Consequently, the performance space becomes ...

David D. Yao

2002-01-01T23:59:59.000Z

457

Environmental design using dynamic insulation  

SciTech Connect

In conventional airtight buildings, the architect has considerable freedom to decide how much the external environment will influence the internal heating, cooling, and ventilation loads. The services engineer provides the plant and equipment required to deal with these loads. This division of labor could lead to undesirable consequences in the case of dynamic insulation, a form of air permeable construction where bulk air flow through the building envelope may be used to either enhance or restrict the conductive heat and mass diffusion fluxes. Small changes in temperature (indoor and out) and wind speed and direction will influence the behavior of a dynamically insulated envelope since the internal and external environments are much more intimately coupled. Buildings employing dynamic insulation thus require good environmental design principles to be applied. The objective of this paper is to lay down rigorous principles that will form the basis of guidelines to architects and building services engineers on how to take account of the ever changing external environment when designing durable and comfortable buildings employing dynamic insulation.

Taylor, B.J.; Imbabi, M.S.

2000-07-01T23:59:59.000Z

458

Conspicuous Consumption and Dynamic Pricing  

Science Conference Proceedings (OSTI)

How do firms develop marketing strategy when consumers seek to satisfy both quality and status-related considerations? We develop an analytical model to study this issue, examining both pricing and product management decisions in markets for conspicuous ... Keywords: conspicuous consumption, durable goods, dynamic pricing, game theory, status

Raghunath Singh Rao, Richard Schaefer

2013-09-01T23:59:59.000Z

459

Dynamical genetic programming in xcsf  

Science Conference Proceedings (OSTI)

A number of representation schemes have been presented for use within learning classifier systems, ranging from binary encodings to artificial neural networks. This paper presents results from an investigation into using a temporally dynamic symbolic ... Keywords: Graph-based genetic programming, XCSF, learning classifier systems, multistep-ahead prediction, reinforcement learning, self-adaptation, symbolic regression

Richard J. Preen, Larry Bull

2013-09-01T23:59:59.000Z

460

Dynamic virtual credit card numbers  

Science Conference Proceedings (OSTI)

Theft of stored credit card information is an increasing threat to e-commerce.We propose a dynamic virtual credit card number scheme that reduces the damage caused by stolen credit card numbers. A user can use an existing credit card account to generate ... Keywords: credit card theft, e-commerce

Ian Molloy; Jiangtao Li; Ninghui Li

2007-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "arcs atomic-scale dynamics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Sheath expansion and plasma dynamics in the presence of electrode evaporation: Application to a vacuum circuit breaker  

Science Conference Proceedings (OSTI)

During the postarc dielectric recovery phase in a vacuum circuit breaker, a cathode sheath forms and expels the plasma from the electrode gap. The success or failure of current breaking depends on how efficiently the plasma is expelled from the electrode gap. The sheath expansion in the postarc phase can be compared to sheath expansion in plasma immersion ion implantation except that collisions between charged particles and atoms generated by electrode evaporation may become important in a vacuum circuit breaker. In this paper, we show that electrode evaporation plays a significant role in the dynamics of the sheath expansion in this context not only because charged particle transport is no longer collisionless but also because the neutral flow due to evaporation and temperature gradients may push the plasma toward one of the electrodes. Using a hybrid model of the nonequilibrium postarc plasma and cathode sheath coupled with a direct simulation Monte Carlo method to describe collisions between heavy species, we present a parametric study of the sheath and plasma dynamics and of the time needed for the sheath to expel the plasma from the gap for different values of plasma density and electrode temperatures at the beginning of the postarc phase. This work constitutes a preliminary step toward understanding and quantifying the risk of current breaking failure of a vacuum arc.

Sarrailh, P. [UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); LAPLACE, CNRS, F-31062 Toulouse (France); Schneider Electric, Centre de Recherche 38 TEC, 38050 Grenoble Cedex 09 (France); Garrigues, L.; Hagelaar, G. J. M.; Boeuf, J. P. [UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); LAPLACE, CNRS, F-31062 Toulouse (France); Sandolache, G.; Rowe, S. [Schneider Electric, Centre de Recherche 38 TEC, 38050 Grenoble Cedex 09 (France)

2009-09-01T23:59:59.000Z